Perovskite solar cell and method of manufacturing the same

Abstract

This invention relates to the field of solar cells and discloses a perovskite solar cell and its fabrication method. The cell has a standard structure, comprising, from bottom to top, a transparent conductive glass layer, an electron transport layer, a bridging molecule modification layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode layer; or, the cell has an inverted structure, comprising, from bottom to top, a transparent conductive glass layer, a hole transport layer, a bridging molecule modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode layer; the structure of the bridging molecule is shown in formula (1), where m is taken from 0, 1, or 2, and n is taken from 0, 1, or 2. The cell structure includes a bridging molecule modification layer, which helps improve the transport performance of the electron transport layer or hole transport layer, reduces carrier interface loss, and simultaneously interacts with the buried interface of the perovskite light-absorbing layer, synergistically passivating to achieve high-quality interface contact, resulting in higher photoelectric conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of solar cells, and more specifically to a perovskite solar cell and its fabrication method. Background Technology

[0002] Perovskite solar cells have increased photoelectric conversion efficiency from an initial 3.8% to over 26% in just over a decade, comparable to commercially available crystalline silicon devices. Therefore, perovskite materials are considered a potential disruptive force in the photovoltaic field. However, the commercialization of perovskite solar cells still faces numerous obstacles. Most notably, current high-efficiency perovskite solar cell devices are fabricated using solution methods. This process, involving annealing and crystallization, generates numerous grain boundaries and defects within and at the interfaces of the perovskite polycrystalline thin film. These defects act as non-radiative recombination sites, trapping photogenerated carriers and severely impairing the performance of the cell. Furthermore, these surface defects and grain boundaries are highly susceptible to erosion by moisture and oxygen, becoming diffusion channels that can deprotonate the perovskite, causing phase transitions or degradation and reducing cell stability.

[0003] Since 2018, a large amount of research has focused on defect passivation at the bulk and surface, including strategies such as additive engineering, solvent engineering, and crystallization control to enhance film quality and reduce bulk defect state density; and methods such as constructing low-dimensional / three-dimensional heterostructures on the surface or using small molecules, polymers, and ionic liquids for surface modification to reduce surface defect density. However, attention has been relatively lacking to the perovskite buried interface (i.e., the electron transport layer / perovskite interface in the formal cell structure, and the hole transport layer / perovskite interface in the inverse structure), which also contains a large number of defects, and the research difficulty is relatively high. The large number of defects at the buried interface not only traps photogenerated carriers and hinders effective charge transport, but also acts as a channel for ion migration, causing charge accumulation at the interface and resulting in a severe photocurrent hysteresis effect, which has a fatal impact on the device and stability of perovskite solar cells. Therefore, it is urgent to passivate defects at the perovskite buried interface to improve the interface contact quality and enhance the photovoltaic performance of the device.

[0004] To address the numerous defects and low interfacial contact quality at the buried perovskite interface, existing solutions similar to this invention include: CN117946160A uses a self-assembled monolayer as a hole transport material to passivate buried perovskite layer defects, release interfacial stress, and improve the photoelectric performance of the battery device; CN117082880A sets protein-functionalized gold nanoclusters between the electron transport layer and the perovskite absorber layer to fill the pores at the buried interface, suppress nonradiative recombination of charge carriers, and enhance charge carrier transport and extraction, resulting in a significant improvement in device efficiency; CN116867342A adds N-chlorosuccinimide to the tin dioxide precursor solution of the electron transport layer, thereby improving the charge carrier transport capability of tin dioxide, passivating defects at the electron transport layer and the buried perovskite interface, and thus improving the photoelectric performance of the device. The methods described above can all passivate defects at the buried interface and improve battery performance, but they all have certain drawbacks. For example, the synthetic routes for self-assembled monolayers, protein-based gold nanoclusters, and N-chlorosuccinimide are relatively complex and the material costs are high. Adding N-chlorosuccinimide to the electron transport layer precursor solution requires changing the process route and readjusting existing mature electron transport layer preparation processes, increasing R&D costs. Therefore, developing a buried interface modification strategy with a simple molecular structure, convenient preparation process, and low cost is crucial. Summary of the Invention

[0005] The purpose of this invention is to provide a perovskite solar cell and its fabrication method. The cell structure includes a bridging molecule modification layer, which helps to improve the transmission performance of the electron transport layer or hole transport layer, reduce carrier interface loss, and at the same time can interact with the buried interface of the perovskite light-absorbing layer to achieve high-quality interface contact through synergistic passivation, so that the cell exhibits higher photoelectric conversion efficiency.

[0006] According to a first aspect of the present invention, the present invention provides a perovskite solar cell, which has a conventional structure and, from bottom to top, comprises a transparent conductive glass layer, an electron transport layer, a bridging molecule modification layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode layer; or, the cell has an inverted structure and, from bottom to top, comprises a transparent conductive glass layer, a hole transport layer, a bridging molecule modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode layer; the structure of the bridging molecule is shown in formula (1).

[0007]

[0008] Where m is taken from 0, 1 or 2, and n is taken from 0, 1 or 2.

[0009] According to a second aspect of the present invention, the present invention provides a method for preparing the perovskite solar cell of the present invention, the method comprising: depositing an electron transport layer on a transparent conductive glass, using the electron transport layer as a substrate, spin-coating a modification solution containing bridging molecules as shown in formula (1) onto the surface of the electron transport layer, and annealing to obtain a bridging molecule modification layer; then sequentially depositing a perovskite light-absorbing layer, depositing a hole transport layer, and evaporating a metal electrode layer to obtain a perovskite solar cell with a formal structure; or, depositing a hole transport layer on a transparent conductive glass, using the hole transport layer as a substrate, spin-coating a modification solution containing bridging molecules as shown in formula (1) onto the surface of the hole transport layer, and annealing to obtain a bridging molecule modification layer; then sequentially depositing a perovskite light-absorbing layer, depositing an electron transport layer, and evaporating a metal electrode layer to obtain a perovskite solar cell with an inverse structure.

[0010] The perovskite solar cell of the present invention includes a bridging molecular modification layer, which helps to improve the transmission performance of the electron transport layer or hole transport layer, reduce carrier interface loss, and at the same time can interact with the buried interface of the perovskite light-absorbing layer to achieve high-quality interface contact through synergistic passivation. This results in the cell having a higher open-circuit voltage and fill factor, thereby exhibiting higher photoelectric conversion efficiency.

[0011] The method for preparing perovskite solar cells provided by this invention has the following advantages:

[0012] 1. The operation process is simple. Only a spin-coating step is needed after the electron transport layer or hole transport layer and before the perovskite light-absorbing layer. No changes to the materials or processes of the electron transport layer or hole transport layer and the perovskite light-absorbing layer are required to achieve the preparation of high-efficiency solar cells.

[0013] 2. The bridging molecules used for modification have simple structures and low material costs. Compared with conventional passivation strategies such as complex macromolecules, ionic liquids, self-assembled monolayers, and the construction of low-dimensional / three-dimensional perovskite heterostructures, they have a significant material cost advantage.

[0014] 3. Modifying the buried interface containing a large number of defects can not only help improve the transmission performance of the electron transport layer or hole transport layer and reduce carrier interface loss, but also interact with the perovskite buried interface to achieve high-quality interface contact through synergistic passivation, thereby preparing a high-efficiency and stable perovskite solar cell. Attached Figure Description

[0015] Figure 1 These are schematic diagrams of (a) the formal structure and (b) the inverse structure of the battery device;

[0016] Figure 2 This is a comparison graph of the current density and voltage of the battery devices prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] According to a first aspect of the present invention, the present invention provides a perovskite solar cell, which has a conventional structure and, from bottom to top, comprises a transparent conductive glass layer, an electron transport layer, a bridging molecule modification layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode layer; or, the cell has an inverted structure and, from bottom to top, comprises a transparent conductive glass layer, a hole transport layer, a bridging molecule modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode layer; the structure of the bridging molecule is shown in formula (1).

[0019]

[0020] Where m is taken from 0, 1 or 2, and n is taken from 0, 1 or 2.

[0021] In this invention, the substituent group on the pyridine ring in formula (1) can be substituted at any carbon position on the pyridine ring.

[0022] In this invention, the transparent conductive glass layer, electron transport layer, perovskite light-absorbing layer, hole transport layer, and metal electrode layer of the perovskite solar cell are all well-known to those skilled in the art. Here, only a brief description of the function of each layer is provided: Transparent conductive glass layer: Allows sunlight to pass through and be transmitted into the cell, while simultaneously collecting the current generated by the perovskite layer; Electron transport layer: Promotes the transfer of electrons from the perovskite layer to the electrode and blocks hole transport; Perovskite light-absorbing layer: Absorbs sunlight and generates photogenerated electrons and holes, a key component for achieving photoelectric conversion and directly affecting the cell's photoelectric conversion performance; Hole transport layer: Promotes the transfer of holes from the perovskite layer to the electrode and blocks electron transport; Metal electrode layer: Collects charge carriers transported from the transport layer, forming a complete current loop and ensuring effective current collection and transmission.

[0023] According to a preferred embodiment of the present invention, in formula (1), m is taken from 0 or 1.

[0024] According to a preferred embodiment of the present invention, in formula (1), n ​​is taken from 0 or 1.

[0025] According to a particularly preferred embodiment of the present invention, in formula (1), m is 0 and n is 1. The perovskite solar cell of the present invention, which satisfies the foregoing features, has the advantages of higher electro-conversion efficiency and lower cost.

[0026] In this invention, there are no special requirements for the thickness of the bridging molecule modification layer. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the thickness of the bridging molecule modification layer is 1-10 nm, for example, 2 nm, 4 nm, 6 nm, 8 nm, etc.

[0027] In this invention, there is no particular limitation on the thickness of the perovskite light-absorbing layer. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the thickness of the perovskite light-absorbing layer is 400-800 nm.

[0028] In this invention, there are no special requirements for the specific substances of the perovskite light-absorbing layer. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the perovskite light-absorbing layer is ABX3; A is selected from one or more of methylamine ions, formamidinium ions and cesium ions, B is lead ions, and X is selected from iodide ions and / or bromide ions.

[0029] In this invention, the perovskite in the perovskite solar cell has a crystal structure, namely the ABX3 structure, which is well known to those skilled in the art.

[0030] According to a preferred embodiment of the present invention, in the ABX3, A comprises methylamine (MA) ions, formamidinium (FA) ions, and cesium (Cs) ions. Based on the total molar content of A, the FA ion content is 80-90%, for example, 82%, 84%, 86%, 88%, etc.; the MA ion content is 5-10%, for example, 6%, 7%, 8%, 9%, etc.; and the cesium ion content is 5-10%, for example, 6%, 7%, 8%, 9%, etc. The battery of the present invention, satisfying the foregoing characteristics, has a higher photoelectric conversion efficiency.

[0031] According to a particularly preferred embodiment of the present invention, in the ABX3, A comprises methylamine ions, formamidinium ions, and cesium ions, and the FA ion content is 88-90% based on the total molar amount of A. The battery of the present invention, satisfying the foregoing characteristics, has a higher photoelectric conversion efficiency.

[0032] According to a preferred embodiment of the present invention, in ABX3, X consists of iodide ions and bromide ions, with the iodide ion content being 95-97% and the bromide ion content being 3-5% based on the total molar amount of X. The battery of the present invention, satisfying the foregoing characteristics, exhibits superior performance.

[0033] In this invention, no special requirements are made for the specific material of the electron transport layer. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the electron transport layer material includes one or more of TiO2, SnO2 and PCBM.

[0034] In this invention, there are no special requirements for the thickness of the electron transport layer. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the thickness of the electron transport layer is 10-30 nm.

[0035] In this invention, the material of the hole transport layer can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the hole transport layer material includes one or more of Spiro-OMeTAD, NiOx and PTAA.

[0036] In this invention, there is no special requirement for the thickness of the hole transport layer. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the thickness of the hole transport layer is 20-150 nm.

[0037] In this invention, there are no special requirements for the selection of the metal electrode layer material. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the metal electrode layer material is selected from Ag and / or Au.

[0038] In this invention, there are no special requirements for the thickness of the metal electrode layer. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the thickness of the metal electrode layer is 60-100 nm.

[0039] In this invention, the transparent conductive glass layer includes a glass substrate layer and a transparent conductive oxide layer. There are no special limitations on the glass substrate material, and it can be selected according to conventional knowledge in the art. There are also no special requirements for the transparent conductive oxide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the transparent conductive oxide is selected from FTO and / or ITO.

[0040] In this invention, there are no special requirements for the thickness of the transparent conductive oxide layer in the transparent conductive glass layer. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the thickness of the transparent conductive glass layer is 100-500 nm.

[0041] In this invention, there are no special requirements or limitations on the thickness of the glass substrate layer in the transparent conductive glass layer.

[0042] In this invention, there are no special requirements for the sheet resistance of the transparent conductive oxide layer, for example, it is 8-14 Ohm / cm. 2 .

[0043] In this invention, the transmittance of the transparent conductive oxide layer is not specifically limited, for example, the transmittance is ≥88%.

[0044] This invention does not impose any special requirements on the preparation method of the perovskite solar cell described herein. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the method includes: depositing an electron transport layer on a transparent conductive glass, using the electron transport layer as a substrate, spin-coating a modification solution containing bridging molecules as shown in formula (1) onto the surface of the electron transport layer, and annealing to obtain a bridging molecule modification layer; then sequentially depositing a perovskite light-absorbing layer, depositing a hole transport layer, and evaporating a metal electrode layer to obtain a perovskite solar cell with a formal structure; or, depositing a hole transport layer on a transparent conductive glass, using the hole transport layer as a substrate, spin-coating a modification solution containing bridging molecules as shown in formula (1) onto the surface of the hole transport layer, and annealing to obtain a bridging molecule modification layer; then sequentially depositing a perovskite light-absorbing layer, depositing an electron transport layer, and evaporating a metal electrode layer to obtain a perovskite solar cell with an inverse structure.

[0045] In this invention, the transparent conductive glass needs to be pretreated before depositing the electron transport layer / hole transport layer on the transparent conductive glass. This is well known to those skilled in the art and will only be briefly described here. The pretreatment can be to use water, ethanol, isopropanol, or acetone to ultrasonically clean the transparent conductive glass for 10-30 minutes. After cleaning, the glass is dried and then subjected to ozone treatment for 10-20 minutes.

[0046] In this invention, the specific operation of depositing the electron transport layer can be carried out in accordance with conventional operations in the field. For example, the water bath method is used, the pretreated transparent conductive glass is placed in a crystallizing dish, and the electron transport layer material is grown in an oven at 70-90°C using the water bath method for 60-80 minutes. After that, it is taken out and dried with a nitrogen gun, and then subjected to ozone treatment for 15-30 minutes.

[0047] In this invention, the concentration of the bridging molecule in the modified solution can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the concentration of the bridging molecule is 0.1-10 mg / ml.

[0048] In this invention, there are no special requirements for the specific type of solvent in the modified solution. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the solvent is selected from one or more of water, ethanol and isopropanol.

[0049] In this invention, the spin coating speed of the modified solution can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the spin coating speed is 1000-3000 rpm.

[0050] In this invention, there are no special requirements for the spin coating time in the modification solution spin coating process. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the spin coating time is 10-30 seconds.

[0051] In this invention, the modification solution is annealed after spin coating. According to a preferred embodiment of the invention, the annealing temperature is 60-100℃.

[0052] In this invention, the modification solution is annealed after spin coating. The annealing time is not particularly important. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the annealing time is 5-10 min.

[0053] In this invention, no special requirements are made for the specific operation of depositing the perovskite light-absorbing layer. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the depositing of the perovskite light-absorbing layer includes: preparing a perovskite mineral solution, spin-coating and adding an antisolvent, and annealing.

[0054] In this invention, there are no special requirements for the content of ABX3 in the perovskite mineral solution. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the content of ABX3 is 1.2-1.8 mol / L.

[0055] In this invention, there is no particular limitation on the specific type of solvent in the perovskite mineral solution. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the solvent is selected from one or more of DMF, DMSO and GBL.

[0056] In this invention, after spin-coating the perovskite mineral solution, an antisolvent needs to be added dropwise to extract the solute from the perovskite solution. There are no special requirements for the specific type of the antisolvent, as long as it is orthogonal to the solvent of the perovskite solution. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the antisolvent is selected from diethyl ether and / or chlorobenzene.

[0057] In this invention, the antisolvent is typically added 20-40 seconds after the spin coating of the perovskite mineral solution is completed, as is well known to those skilled in the art.

[0058] In this invention, the spin coating speed in the spin coating of perovskite mineral solution can be selected from a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the spin coating speed is 3000-6000 rpm.

[0059] In this invention, there are no special requirements for the spin-coating time in the spin-coating of the perovskite mineral solution. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the spin-coating time is 20-60 seconds.

[0060] In this invention, the perovskite mineral solution is spin-coated, an antisolvent is added dropwise, and then annealed. There are no special requirements for the annealing temperature. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the annealing temperature is 100-150°C.

[0061] In this invention, the perovskite mineral solution is spin-coated, an antisolvent is added, and then annealed. There are no special requirements for the annealing time. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the annealing time is 10-30 minutes.

[0062] In this invention, the specific operation of depositing the hole transport layer can be carried out in accordance with conventional operations in the field. For example, after preparing the hole transport layer material solution, spin coating and annealing can be performed. The spin coating speed can be 2000-5000 rpm and the spin coating time can be 20-50 s.

[0063] In this invention, there are no special requirements for the specific operation of preparing the metal electrode layer. For example, the metal electrode layer can be prepared by vacuum evaporation.

[0064] The present invention will be described in detail below through embodiments.

[0065] In the following embodiments,

[0066] All solid raw materials used are commercially available products from Liaoning Youxuan New Energy Technology Co., Ltd., and all liquid raw materials are commercially available products from Sigma-Aldrich, Inc. of the United States.

[0067] In this embodiment of the invention, the effective area of ​​the prepared battery electrode is 0.09 cm². 2 .

[0068] Example 1

[0069] (1) Treatment of transparent conductive glass layer: The FTO glass was ultrasonically cleaned with water, acetone, isopropanol and ethanol respectively for 30 min, and then dried and treated with ozone for 15 min; the thickness of the FTO layer in the FTO glass was 350 nm and the sheet resistance was 13 Ohm / cm 2The light transmittance is 89%;

[0070] (2) Deposition of electron transport layer: The pretreated FTO glass was placed in a crystallizing dish and TiO2 was grown in a 70℃ oven using a water bath method. After 60 min, it was taken out, dried with a nitrogen gun, and treated with ozone for 15 min. The thickness of the electron transport layer was 25 nm.

[0071] (3) Preparation of bridging molecule modification layer: spin-coating p-acetylpyridine solution (concentration of 1 mg / ml, solvent of isopropanol) onto the electron transport layer obtained in step (2) at a spin-coating speed of 3000 rpm for 30 s, followed by annealing at 70 °C for 5 min; the thickness of the bridging molecule modification layer is 3 nm.

[0072] (4) Deposition of perovskite light-absorbing layer: A perovskite mineral solution (perovskite formulation is FA) is spin-coated onto the bridged molecular modification layer obtained in step (3). 0.85 MA 0.1 Cs 0.05 PbI 2.91 Br 0.09 The concentration was 1.5 mol / L, the solvent was 80 wt% DMF + 20 wt% DMSO, the spin coating speed was 5000 rpm, the time was 50 s, and the anti-solvent (diethyl ether) was added 30 s after spin coating. Then, the mixture was annealed at 150 °C for 15 min. The thickness of the perovskite light-absorbing layer was 550 nm.

[0073] (5) Deposition of hole transport layer: Spiro-OMeTAD solution (90 mg / mL, solvent is chlorobenzene) is spin-coated onto the perovskite light-absorbing layer obtained in step (4) at a spin speed of 3000 rpm for 30 s; the hole transport layer thickness is 90 nm.

[0074] (6) Preparation of metal electrode layer: The sample obtained in step (5) is fixed on a mask, and Au electrode material is deposited on the hole transport layer by vacuum evaporation, with an electrode thickness of 80 nm.

[0075] The structure of the prepared battery device is as follows Figure 1 As shown in (a).

[0076] Example 2

[0077] (1) Treatment of transparent conductive glass layer: The FTO glass was ultrasonically cleaned with water, acetone, isopropanol and ethanol respectively for 30 min, and then dried and treated with ozone for 15 min; the thickness of the FTO layer in the FTO glass was 350 nm and the sheet resistance was 13 Ohm / cm 2 The light transmittance is 89%;

[0078] (2) Deposition of electron transport layer: The pretreated FTO glass was placed in a crystallizing dish and TiO2 was grown in a 70℃ oven using a water bath method. After 60 min, it was taken out, dried with a nitrogen gun, and treated with ozone for 15 min. The thickness of the electron transport layer was 25 nm.

[0079] (3) Preparation of bridging molecular modification layer: spin-coating modification solution (0.1 mg / ml of o-acetylpyridine, ethanol as solvent) onto the electron transport layer obtained in step (2) at a spin-coating speed of 2000 rpm for 30 s, followed by annealing at 60 °C for 8 min; the thickness of the bridging molecular modification layer is 4 nm.

[0080] (4) Deposition of perovskite light-absorbing layer: A perovskite mineral solution (perovskite formulation is FA) is spin-coated onto the bridged molecular modification layer obtained in step (3). 0.87 MA 0.08 Cs 0.05 PbI 2.85 Br 0.15 The concentration was 1.2 mol / L, the solvent was 80 wt% DMF + 20 wt% GBL, the spin coating speed was 4000 rpm, the time was 60 s, and the anti-solvent (diethyl ether) was added 30 s after spin coating. Then, the mixture was annealed at 120 °C for 20 min. The thickness of the perovskite light-absorbing layer was 600 nm.

[0081] (5) Deposition of hole transport layer: Spiro-OMeTAD solution (90 mg / mL, solvent is chlorobenzene) is spin-coated onto the perovskite light-absorbing layer obtained in step (4) at a spin speed of 3000 rpm for 30 s; the hole transport layer thickness is 90 nm.

[0082] (6) Preparation of metal electrode layer: Fix the sample obtained in step (5) on a mask, and use vacuum evaporation to deposit Ag electrode material on the hole transport layer. The electrode thickness is 100 nm.

[0083] The structure of the prepared battery device is as follows Figure 1 As shown in (a).

[0084] Example 3

[0085] (1) Treatment of transparent conductive glass layer: The FTO glass was ultrasonically cleaned with water, acetone, isopropanol and ethanol respectively for 30 min, and then dried and treated with ozone for 15 min; the thickness of the FTO layer in the FTO glass was 150 nm and the sheet resistance was 9 Ohm / cm 2 The light transmittance is 89%;

[0086] (2) Deposition of electron transport layer: The pretreated ITO glass was placed in a crystallizing dish and SnO2 was grown in a 70°C oven using a water bath method. After 60 min, it was taken out, dried with a nitrogen gun, and treated with ozone for 15 min. The thickness of the electron transport layer was 30 nm.

[0087] (3) Preparation of bridging molecular modification layer: spin-coating modification solution (10 mg / ml p-propionylpyridine concentration, isopropanol solvent) onto the electron transport layer obtained in step (2) at a spin speed of 1500 rpm for 20 s, followed by annealing at 80 °C for 9 min; the thickness of the bridging molecular modification layer is 5 nm.

[0088] (4) Deposition of perovskite light-absorbing layer: A perovskite mineral solution (perovskite formulation is FA) is spin-coated onto the bridged molecular modification layer obtained in step (3). 0.82 MA 0.1 Cs 0.08 PbI 2.88 Br 0.12 The concentration was 1.8 mol / L, the solvent was 80% DMF + 20% DMSO, the spin coating speed was 6000 rpm, the time was 50 s, and the anti-solvent (chlorobenzene) was added 30 s after spin coating. Then, the mixture was annealed at 150 °C for 10 min. The thickness of the perovskite light-absorbing layer was 500 nm.

[0089] (5) Deposition of hole transport layer: Spiro-OMeTAD solution (90 mg / mL, solvent is chlorobenzene) is spin-coated onto the perovskite light-absorbing layer obtained in step (4) at a spin speed of 3000 rpm for 30 s; the hole transport layer thickness is 90 nm.

[0090] (6) Preparation of metal electrode layer: The sample obtained in step (5) is fixed on a mask, and gold electrode material is deposited on the hole transport layer by vacuum evaporation, with an electrode thickness of 60 nm.

[0091] The structure of the prepared battery device is as follows Figure 1 As shown in (a).

[0092] Example 4

[0093] (1) Treatment of transparent conductive glass layer: The ITO glass was ultrasonically cleaned with water, acetone, isopropanol and ethanol respectively for 30 min, and then dried and treated with ozone for 15 min; the thickness of the ITO layer in the ITO glass was 100 nm and the sheet resistance was 10 Ohm / cm 2 The light transmittance is 90%.

[0094] (2) Deposition of hole transport layer: NiOx solution (8 mg / ml, solvent is water) was spin-coated onto the pretreated ITO substrate at a spin speed of 4000 rpm for 40 s. After spin-coating, the substrate was annealed at 150 °C for 15 min. The hole transport layer thickness was 30 nm.

[0095] (3) Preparation of bridging molecule modification layer: spin-coating modification solution (1 mg / ml of p-acetylpyridine, isopropanol as solvent) onto the hole transport layer obtained in step (2) at a spin speed of 3000 rpm for 30 s, followed by annealing at 70 °C for 5 min; the thickness of the bridging molecule modification layer is 3 nm.

[0096] (4) Deposition of perovskite light-absorbing layer: A perovskite mineral solution (perovskite formulation is FA) is spin-coated onto the bridged molecular modification layer obtained in step (3). 0.85 MA 0.1 Cs 0.05 PbI 2.91 Br 0.09 The concentration was 1.2 mol / L, the solvent was 80% DMF + 20% DMSO, the spin coating speed was 5500 rpm, the time was 50 s, and the anti-solvent (diethyl ether) was added 30 s after spin coating. Then, the mixture was annealed at 150 °C for 10 min. The thickness of the perovskite light-absorbing layer was 550 nm.

[0097] (5) Deposition of electron transport layer: Spin-coating PCBM solution (20 mg / mL, solvent is chlorobenzene) onto the perovskite light-absorbing layer obtained in step (4) at a spin speed of 3000 rpm for 30 s; the thickness of the electron transport layer is 30 nm.

[0098] (6) Preparation of metal electrode layer: Fix the sample obtained in step (5) on a mask, and use vacuum evaporation to deposit silver electrode material on the electron transport layer with a thickness of 100 nm.

[0099] The structure of the prepared battery device is as follows Figure 1 As shown in (b).

[0100] Example 5

[0101] The method is the same as in Example 1, except that the perovskite formulation is replaced with FA. 0.9 MA 0.05 Cs 0.05 PbI 2.91 Br 0.09 .

[0102] The structure of the prepared battery device is as follows Figure 1 As shown in (a).

[0103] Example 6

[0104] The method is the same as in Example 1, except that the modification solution is a pyridine-4-carboxaldehyde solution (1 mg / ml, isopropanol as solvent).

[0105] The structure of the prepared battery device is as follows Figure 1 As shown in (a).

[0106] Comparative Example 1

[0107] (1) Treatment of transparent conductive glass layer: The FTO glass was ultrasonically cleaned with water, acetone, isopropanol and ethanol respectively for 30 min, and then dried and treated with ozone for 15 min; the thickness of the FTO layer was 350 nm and the sheet resistance was 13 Ohm / cm. 2 The light transmittance is 89%;

[0108] (2) Deposition of electron transport layer: The pretreated FTO glass was placed in a crystallizing dish and TiO2 was grown in a 70℃ oven using a water bath method. After 60 min, it was taken out, dried with a nitrogen gun, and treated with ozone for 15 min. The thickness of the electron transport layer was 25 nm.

[0109] (3) Deposition of perovskite light-absorbing layer: A perovskite mineral solution (perovskite formulation is FA) is spin-coated onto the electron transport layer obtained in step (2). 0.85 MA 0.1 Cs 0.05 PbI 2.91 Br 0.09 The concentration was 1.5 mol / L, the solvent was 80 wt% DMF + 20 wt% DMSO, the spin coating speed was 5000 rpm, the time was 50 s, and the anti-solvent (diethyl ether) was added 30 s after spin coating. Then, the mixture was annealed at 150 °C for 15 min. The thickness of the perovskite light-absorbing layer was 550 nm.

[0110] (4) Deposition of hole transport layer: Spiro-OMeTAD solution (90 mg / mL, solvent is chlorobenzene) is spin-coated onto the perovskite light-absorbing layer obtained in step (3) at a spin speed of 3000 rpm for 30 s; the hole transport layer thickness is 90 nm.

[0111] (5) Preparation of metal electrode layer: The sample obtained in step (4) is fixed on a mask, and Au electrode material is deposited on the hole transport layer by vacuum evaporation, with an electrode thickness of 80 nm.

[0112] Comparative Example 2

[0113] The method is the same as in Example 1, except that the modification solution is an acetone solution (1 mg / ml, isopropanol as solvent).

[0114] Comparative Example 3

[0115] The method is the same as in Example 1, except that the modification solution is an o-methylpyridine solution (1 mg / ml, solvent is isopropanol).

[0116] Comparative Example 4

[0117] The method is the same as in Example 1, except that the modification solution is a phenylethylamine solution (1 mg / ml, isopropanol as solvent).

[0118] [Battery Performance Test]

[0119] Test method: The unencapsulated battery device prepared above was used for IV curve testing. The testing instrument was a solar simulator, the solar spectrum was AM 1.5G, and the light intensity was 100mW / cm². 2 The test voltage was 0-1.5V, with a step size of 2mV and an interval of 10ms. The open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency were obtained from the IV curves obtained under illumination. Specific data are shown in Table 1, along with a comparison of the current density-voltage of the battery devices prepared in Example 1 (after modification) and Comparative Example 1 (before modification). Figure 2 As shown, the efficiency of the battery device was significantly improved after modification with bridging molecules.

[0120] Photovoltaic conversion efficiency (%) = Open circuit voltage × Short circuit current density × Fill factor.

[0121] Table 1

[0122]

[0123] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A perovskite solar cell, characterized in that, The battery has a standard structure, which, from bottom to top, includes a transparent conductive glass layer, an electron transport layer, a bridging molecule modification layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode layer; or, the battery has an inverted structure, which, from bottom to top, includes a transparent conductive glass layer, a hole transport layer, a bridging molecule modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode layer. The structure of the bridging molecule is shown in formula (1). Where m is taken from 0, 1 or 2, and n is taken from 0, 1 or 2.

2. The battery according to claim 1, characterized in that, In equation (1), m is taken from 0 or 1; and / or n can be either 0 or 1.

3. The battery according to claim 1 or 2, characterized in that, In equation (1), m is 0 and n is 1.

4. The battery according to claim 1 or 2, characterized in that, The thickness of the bridging molecular modification layer is 1-10 nm.

5. The battery according to claim 1 or 2, characterized in that, The thickness of the perovskite light-absorbing layer is 400-800 nm; and / or The perovskite light-absorbing layer contains ABX3 perovskite minerals; A is selected from one or more of methylamine ions, formamidinium ions, and cesium ions, B is lead ions, and X is selected from iodide ions and / or bromide ions.

6. The battery according to claim 5, characterized in that, A includes methylamine ions, formamidinium ions, and cesium ions. Based on the total molar amount of A, the content of formamidinium ions is 80-90%, the content of methylamine ions is 5-10%, and the content of cesium ions is 5-10%.

7. The battery according to claim 6, characterized in that, Based on the total molar amount of A, the formamidinium ion content is 88-90%.

8. The battery according to claim 5 or 6, characterized in that, X includes iodide ions and bromide ions. Based on the total molar amount of X, the content of iodide ions is 95-97%, and the content of bromide ions is 3-5%.

9. The battery according to claim 1 or 2, characterized in that, The electron transport layer material includes one or more of TiO2, SnO2, and PCBM; and / or The thickness of the electron transport layer is 10-30 nm; and / or The hole transport layer material includes one or more of Spiro-OMeTAD, NiOx, and PTAA; and / or The hole transport layer has a thickness of 20-150 nm; and / or The metal electrode layer material is selected from Ag and / or Au; and / or The thickness of the metal electrode layer is 60-100 nm; and / or The transparent conductive glass layer includes a glass substrate layer and a transparent conductive oxide layer; the transparent conductive oxide is selected from FTO and / or ITO; the thickness of the transparent conductive oxide layer is 100-500 nm.

10. The method for preparing the perovskite solar cell according to claim 1 or 2, characterized in that, The method includes: An electron transport layer is deposited on a transparent conductive glass. Using the electron transport layer as a substrate, a modification solution containing the bridging molecule shown in formula (1) is spin-coated onto the surface of the electron transport layer. After annealing, a bridging molecule modification layer is obtained. Then, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode layer are deposited sequentially to obtain a perovskite solar cell with the formal structure. Alternatively, a hole transport layer is deposited on a transparent conductive glass. Using the hole transport layer as a substrate, a modification solution containing the bridging molecules shown in formula (1) is spin-coated onto the surface of the hole transport layer. After annealing, a bridging molecule modification layer is obtained. Then, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode layer are deposited sequentially to obtain a perovskite solar cell with an inverted structure.

11. The method according to claim 10, characterized in that, In the modified solution The concentration of the bridging molecule is 0.1-10 mg / ml; and / or The solvent is selected from one or more of water, ethanol and isopropanol.

12. The method according to claim 10 or 11, characterized in that, The spin coating conditions include: a spin coating speed of 1000-3000 rpm; and / or a spin coating time of 10-30 s; and / or The annealing conditions include: an annealing temperature of 60-100℃; and / or an annealing time of 5-10 min.

13. The method according to claim 10 or 11, characterized in that, The deposited perovskite light-absorbing layer comprises: preparing a perovskite mineral solution, spin-coating and adding an antisolvent, and annealing.

14. The method according to claim 13, characterized in that, In the perovskite mineral solution The concentration of ABX3 is 1.2-1.8 mol / L; and / or The solvent is selected from one or more of DMF, DMSO and GBL.

15. The method according to claim 13 or 14, characterized in that, The antisolvent is selected from diethyl ether and / or chlorobenzene.

16. The method according to claim 13 or 14, characterized in that, The spin coating conditions include: a spin coating speed of 3000-6000 rpm; and / or a spin coating time of 20-60 s; and / or The annealing conditions include: an annealing temperature of 100-150℃; and / or an annealing time of 10-30 min.

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