Large-area perovskite thin film layer, preparation method and application thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KUNSHAN GCL OPTOELECTRONIC MATERIAL CO LTD
- Filing Date
- 2022-06-20
- Publication Date
- 2026-07-10
AI Technical Summary
During the fabrication of perovskite solar cells, dislocations, interstitial defects, and grain boundaries are easily generated when perovskite films are deposited over a large area, leading to increased recombination. Furthermore, the inhomogeneity of perovskite lattices with different compositions is difficult to control.
By applying pressure to the surface of the perovskite film while it is in a small crystalline state, and combining this with annealing, dislocations and interstitial defects in the perovskite film can be repaired. Pressure annealing is performed in a manner similar to lamination to form a more perfect crystalline structure.
This improved the open-circuit voltage of the device, reduced grain boundary recombination of charge carriers, enhanced interfacial contact, and improved the crystallization quality and production efficiency of the thin film.
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Figure CN115101678B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of solar cell technology, specifically relating to a large-area perovskite thin film layer, its preparation method, and its application. Background Technology
[0002] In recent years, with the continuous deepening of research, perovskite solar cells have made rapid progress, with efficiency increasing from the initial 3.8% to 25.7%, and are hailed as "new hope in the photovoltaic field".
[0003] Common perovskite solar cell structures are categorized into mesoscopic structures, mesoscopic superstructures, planar nip-type structures, and planar pin-type structures. Regardless of the structure, the fabrication of the perovskite layer is crucial, determining the overall device efficiency. An ideal perovskite solar cell requires complete crystal growth, few internal defects, and minimal interface defect recombination. To achieve better device efficiency, optimization is generally approached from two angles: improving the crystallinity of the perovskite itself and using interface modification methods. Existing perovskite solar cell fabrication processes suffer from the following problems: 1. Large-area perovskite deposition leads to dislocations and interstitial defects in the thin film, generating numerous grain boundaries and causing recombination; 2. The formation of perovskite lattices with different compositions cannot be completely controlled, resulting in inhomogeneity of the perovskite layer. Summary of the Invention
[0004] The main objective of this invention is to provide a large-area perovskite thin film layer, its preparation method, and its application, so as to overcome the shortcomings of the prior art.
[0005] To achieve the aforementioned objectives, the technical solutions adopted in the embodiments of the present invention include:
[0006] This invention provides a method for preparing a large-area perovskite thin film layer, comprising:
[0007] A perovskite precursor solution is coated onto the substrate surface to form a first precursor film.
[0008] The first precursor film is pre-annealed to form a second precursor film containing fragmented crystals.
[0009] Pressure is applied to the second precursor film, the pressure being perpendicular to the film plane of the second precursor film, while the second precursor film is annealed.
[0010] Furthermore, the method for preparing the large-area perovskite thin film layer includes: after forming the first precursor film, drying the first precursor film, and then performing the pre-annealing treatment.
[0011] Furthermore, the method for preparing the large-area perovskite thin film layer specifically includes: applying the pressure to the second precursor film through a pressure plate, wherein the pressure surface of the pressure plate is a plane; wherein the pressure surface of the pressure plate is in direct contact with the second precursor film, or a liquid film is distributed between the pressure surface of the pressure plate and the second precursor film, wherein the liquid film is formed by an inert solvent.
[0012] This invention also provides a large-area perovskite thin film layer prepared by the aforementioned method.
[0013] This invention also provides a photovoltaic device, comprising a first electrode, a first carrier transport layer, an active layer, a second carrier transport layer, and a second electrode arranged sequentially along a predetermined direction; wherein the active layer comprises the aforementioned large-area perovskite thin film layer.
[0014] Furthermore, the photovoltaic device further includes a first interface modification layer and / or a second interface modification layer, wherein the first interface modification layer is disposed between the first carrier transport layer and the active layer, and the second interface modification layer is disposed between the second carrier transport layer and the active layer.
[0015] Compared with the prior art, the present invention has the following beneficial effects:
[0016] (1) The method for preparing a large-area perovskite thin film layer of the present invention involves increasing pressure on the surface of the perovskite thin film when the perovskite is in a small crystalline state, thereby eliminating defects such as dislocations and gaps formed in the pre-crystallized state. In the subsequent annealing process, the crystallization is further improved, forming a better perovskite thin film, which can effectively improve the open-circuit voltage of the device. Moreover, the method is simple and can be prepared using mature large-area process equipment, making it easy to scale up production. In addition, by applying pressure to anneal the perovskite thin film with a fragmented crystal state in a similar lamination manner, the grain boundaries caused by the small fragments formed during the drying process of the perovskite are repaired, reducing the recombination of charge carriers at the grain boundaries.
[0017] (2) During the preparation process of the large-area perovskite thin film layer of the present invention, it can make closer contact with the bottom, form better interface contact, reduce interface recombination, and be subjected to uniform high pressure at the top, which can form a smoother perovskite thin film, resulting in higher film quality in the subsequent film formation.
[0018] (3) By adding high pressure, the present invention reduces the voids generated in the film during the liquid removal process, reduces the formation of defects such as dislocations after film crystallization, and thus reduces the grain boundaries of the film and the loss of charge carriers at the grain boundaries. This can make the film surface smoother and increase the deposition quality of other films in subsequent steps. It can also control the perovskite crystal form, realize the repair of perovskite crystals during the amplification process, improve the quality of crystallization, increase the yield of products, and improve production efficiency. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 This is a schematic diagram of the morphology of the perovskite layer in Embodiment 1 of this application.
[0021] Figure 2 This is a schematic diagram of the morphology of the perovskite layer in Comparative Example 2 of this application. Detailed Implementation
[0022] In view of the shortcomings of existing technologies, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. It mainly addresses the defects caused by the formation of dislocations and interstitial defects in perovskite films during large-area film deposition, resulting in numerous grain boundaries and composite formation; and the inability to completely control the formation of perovskite lattices of different compositions, leading to inhomogeneity in the perovskite layer. By developing a large-area perovskite thin film layer and its preparation method and application, pressure is applied to the surface of the perovskite film during its small crystalline state, causing the dislocations and interstitial defects formed in the pre-crystallized state to disappear. Further annealing in the subsequent process further perfects the crystallization, forming a better perovskite thin film, which can effectively improve the open-circuit voltage of the device. The following will further explain and illustrate this technical solution, its implementation process, and its principles.
[0023] Key points to note in the preparation of the perovskite thin film layer of this invention: 1. The preparation process must be semi-solid to control the formation of the perovskite lattice and the bonding of two different perovskites; 2. An annealing mechanism with certain temperature control is required; 3. The pressure needs to be precisely and uniformly controlled; 4. Pressurized annealing is carried out using a flat plate or a flat plate + inert solvent in a manner similar to lamination.
[0024] One aspect of this invention provides a method for preparing a large-area perovskite thin film layer, comprising:
[0025] A perovskite precursor solution is coated onto the substrate surface to form a first precursor film.
[0026] The first precursor film is pre-annealed to form a second precursor film containing fragmented crystals.
[0027] Pressure is applied to the second precursor film, the pressure being perpendicular to the film plane of the second precursor film, while the second precursor film is annealed.
[0028] In some preferred embodiments, the method for preparing the large-area perovskite thin film layer includes: after forming the first precursor film, drying the first precursor film, and then performing the pre-annealing treatment.
[0029] In some preferred embodiments, the temperature of the pre-annealing treatment is 70-100°C.
[0030] In some preferred embodiments, the pressure is 0.1-200 MPa.
[0031] In some preferred embodiments, the method for preparing the large-area perovskite thin film layer specifically includes: applying the pressure to the second precursor film through a pressure plate, wherein the pressure surface of the pressure plate is a plane; wherein the pressure surface of the pressure plate is in direct contact with the second precursor film, or a liquid film is distributed between the pressure surface of the pressure plate and the second precursor film, wherein the liquid film is formed by an inert solvent.
[0032] In some more preferred embodiments, the pressure plate comprises a polytetrafluoroethylene (PTFE) flat plate, but is not limited thereto.
[0033] In some more preferred embodiments, the inert solvent includes any one or more combinations of chlorobenzene, n-butanol, n-pentanol, or ethyl acetate, but is not limited thereto.
[0034] In some preferred embodiments, the annealing treatment is performed at a temperature of 100-150°C for 10-30 minutes.
[0035] Another aspect of the present invention provides a large-area perovskite thin film layer prepared by the aforementioned method.
[0036] Another aspect of the present invention provides a photovoltaic device, comprising a first electrode, a first carrier transport layer, an active layer, a second carrier transport layer, and a second electrode arranged sequentially along a predetermined direction; wherein the active layer comprises the aforementioned large-area perovskite thin film layer.
[0037] In some preferred embodiments, the photovoltaic device further includes a first interface modification layer and / or a second interface modification layer, wherein the first interface modification layer is disposed between the first carrier transport layer and the active layer, and the second interface modification layer is disposed between the second carrier transport layer and the active layer.
[0038] In some preferred embodiments, the photovoltaic device is a forward-facing structure or an inverted structure.
[0039] In some preferred embodiments, the photovoltaic device has a planar pin-type structure.
[0040] This invention employs a lamination-like method to pressure-anneal perovskite films in a fragmented state, repairing grain boundaries caused by small fragments formed during the drying process and reducing carrier recombination at grain boundaries. Specifically, by applying pressure to the perovskite film surface while it is in a small crystalline state, defects such as dislocations and gaps formed in the pre-crystallized state disappear, leading to more complete crystallization during subsequent annealing and the formation of a better perovskite film. This effectively improves the open-circuit voltage of the device. Furthermore, the method is simple, can be fabricated using mature large-area process equipment, and is easily scaled up for production.
[0041] In the specific implementation process, the first interface modification layer and the second interface modification layer are respectively one of the electron doping layer and the hole doping layer; the first carrier transport layer and the second carrier transport layer are respectively one of the electron transport layer and the hole transport layer.
[0042] In some preferred embodiments, the first electrode may be selected from one of FTO conductive glass, ITO conductive glass, FTO conductive plastic, and ITO conductive plastic, but is not limited thereto; wherein the FTO thickness is 500nm and the ITO thickness is 300-400nm.
[0043] In some preferred embodiments, when the photovoltaic device is a forward structure, the material of the electron transport layer can be selected from any one of TiO2, ZnO2, SnO2, ZnSnOx, CdS, and CdSe, but is not limited to this, and its thickness is 10-50 nm; the electron doping layer is SnO2 doped with In2O3, and the doping ratio is between 20:80 and 50:50; the perovskite layer has the structural formula MAPbI3 (the structural formula of MA is CH3NH3). + );FA x Cs y MA 1-x-y Pb(I a Br b Cl 1-a-b )3; (The structural formula of FA is CH4N2) + The thickness is 300-1000nm; the hole doping layer is Cu2PbI4Tu2 with a thickness of 1-5nm; the hole transport layer is made of any one of (NiOx:Cu), CuI, CuSCN, and Cu2O, but is not limited to this, and its thickness is 300-600nm.
[0044] In some preferred embodiments, when the photovoltaic device is a reverse structure, the hole transport layer is made of any one of NiOx, CuI, CuSCN, and Cu2O, but is not limited to this, and its thickness is 15-40 nm; the hole doping layer is Cu2PbI4Tu2, and its thickness is 1-5 nm; the perovskite layer has the structural formula MAPbI3 (the structural formula of MA is CH3NH3). + ) or FA x Cs y MA 1-x-y Pb(I a Br b Cl 1-a-b )3, with a thickness of 300-1000nm; the electron doping layer is a certain ratio of In2O3:SnO2, with a ratio range of 20:80 to 50:50, and its thickness is 1-3nm; the material of the electron transport layer can be selected from any one of TiOx, SnO2, ZnO, ZnSnOx, CdS, and CdSe, but is not limited to this, and its thickness is 3-10nm.
[0045] In some preferred embodiments, the second electrode is a metal electrode or a transparent electrode.
[0046] In some more preferred embodiments, the metal electrode may be selected from any metal such as Ag, Al, Au, etc., but is not limited thereto.
[0047] In some more preferred embodiments, the transparent electrode may be selected from one or more of metal oxides, silver nanowires, transparent conductive polymer materials, etc., but is not limited thereto; wherein the metal oxide may be selected from ITO or IWO, but is not limited thereto.
[0048] When the photovoltaic device is a forward structure, the thickness of the second electrode is 100-200 nm; when the perovskite cell module is a reverse structure, the thickness of the second electrode is 100-400 nm.
[0049] The technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0050] Example 1
[0051] The perovskite solar cell provided in this embodiment has a forward structure, which includes a conductive substrate, an electron transport layer, an electron doping layer, a perovskite layer, a hole doping layer, a hole transport layer, and an electrode.
[0052] The conductive substrate is one of FTO conductive glass, ITO conductive glass, FTO conductive plastic, or ITO conductive plastic, with FTO having a thickness of approximately 500 nm and ITO having a thickness of approximately 300-400 nm; the electron transport layer is any one of TiO2, ZnO2, SnO2, ZnSnOx, CdS, or CdSe, with a thickness of approximately 10-50 nm; the electron doping layer is SnO2 doped with In2O3, with a doping ratio between 20:80 and 50:50; the perovskite MAPbI3 (MA) has the structural formula CH3NH3. + );FA x Cs y MA 1-x-y Pb(I a Br b Cl 1-a-b )3; (The structural formula of FA is CH4N 2+ The thickness is 300-1000 nm; the hole doping layer is Cu2PbI4Tu2 with a thickness of 1-5 nm; the hole transport layer is any one of (NiOx:Cu), CuI, CuSCN, and Cu2O with a thickness of 300-600 nm; the metal electrode is Ag, Al, or Au; and the transparent electrode is any one of IWO and ITO with a thickness of approximately 100-200 nm.
[0053] A method for preparing the perovskite solar cell includes:
[0054] (1) An electron transport layer and an electron doping layer are sequentially prepared on a conductive substrate in accordance with methods known in the art;
[0055] (2) A 0.7 mol / L perovskite precursor solution is coated onto an electron-doped layer to form a first precursor film by spin coating with vacuuming or coating with blowing.
[0056] (3) The first precursor film is pre-annealed at 70°C for 1 min to form a second precursor film containing fragmented crystals;
[0057] (4) Apply a pressure of 0.1 MPa to the second precursor film using a polytetrafluoroethylene plate and anneal at 70°C for 30 min to form a perovskite layer.
[0058] (5) A hole-doped layer, a hole transport layer, and a metal electrode are disposed on the perovskite layer in a manner known in the art.
[0059] Comparative Example 1:
[0060] The comparative example is basically the same as Example 1, except that in step (3), the second precursor film is completely dried directly during the pre-annealing process.
[0061] Comparative Example 2:
[0062] The comparative example is basically the same as Example 1, except that: in step (4), no pressure was applied to the second precursor film, but it was annealed at 100°C for 30 minutes.
[0063] The perovskite device of Example 1 was used as the pressurized sample, and the perovskite device of Comparative Example 2 was used as the reference sample. Their morphological comparisons are shown in [Figure 1]. Figure 1 and Figure 2 Performance tests were conducted, and the results are shown in the table below:
[0064]
[0065] As shown in the table above, the pressure annealing method in this embodiment of the invention can effectively improve the open-circuit voltage of the device, and through... Figure 1 and Figure 2 As can be seen from the comparison, the perovskite layer in the technical solution of the present invention can make closer contact with the bottom, forming a better interface contact, reducing interface recombination, and being subjected to uniform high pressure at the top, it can form a smoother perovskite film.
[0066] Example 2
[0067] The structure of the perovskite solar cell provided in this embodiment is basically the same as that in Embodiment 1.
[0068] A method for preparing the perovskite solar cell includes:
[0069] (1) An electron transport layer and an electron doping layer are sequentially prepared on a conductive substrate in accordance with methods known in the art;
[0070] (2) A 1.7 mol / L perovskite precursor solution is coated onto an electron-doped layer to form a first precursor film by spin coating with vacuuming or coating with blowing.
[0071] (3) The first precursor film is pre-annealed at 100°C for 5 min to form a second precursor film containing fragmented crystals;
[0072] (4) A liquid film is formed on the second precursor film with ethyl acetate, and a pressure of 200 MPa is applied to the second precursor film using a polytetrafluoroethylene plate and the liquid film, while annealing at 100°C for 10 min to form a perovskite layer.
[0073] (5) A hole-doped layer, a hole transport layer, and an electrode are disposed on the perovskite layer in a manner known in the art.
[0074] Example 3
[0075] This embodiment provides a perovskite solar cell with a reverse structure, comprising a conductive substrate, a hole transport layer, a hole doping layer, a perovskite layer, an electron doping layer, an electron transport layer, and a metal electrode. The materials and thicknesses of each layer are as follows: the conductive substrate is one of FTO conductive glass, ITO conductive glass, FTO conductive plastic, or ITO conductive plastic, with FTO having a thickness of approximately 500 nm and ITO having a thickness of approximately 300-400 nm; the hole transport layer is NiOx, CuI, CuSCN, or Cu2O, with a thickness of approximately 15-40 nm; the hole doping layer is Cu2PbI4Tu2, approximately 1-5 nm thick; and the perovskite MAPbI3 (MA has the structural formula CH3NH3) is also present. + ) or FA x Cs y MA 1-x-y Pb(I a Br b Cl 1-a-b 3. The thickness is 300-1000 nm. The electron doping layer is a certain ratio of In2O3:SnO2, with a ratio range of 20:80 to 50:50. The thickness of the doped layer is 1-3 nm. The electron transport layer is any one of TiOx, SnO2, ZnO or ZnSnOx, CdS, CdSe, with a thickness of about 3-10 nm. The metal electrode is any one of Ag, Al or Au or ITO, IWO transparent electrode, with a thickness of about 100-400 nm.
[0076] A method for preparing the perovskite solar cell includes:
[0077] (1) A hole transport layer and a hole doping layer are sequentially prepared on a conductive substrate in accordance with methods known in the art;
[0078] (2) A 1.2 mol / L perovskite precursor solution is coated onto the hole-doped layer to form a first precursor film by spin coating with vacuuming or coating with blowing.
[0079] (3) The first precursor film is pre-annealed at 70°C for 3 min to form a second precursor film containing fragmented crystals;
[0080] (4) Apply a pressure of 0.1 MPa to the second precursor film using a polytetrafluoroethylene plate and anneal at 70°C for 30 min to form a perovskite layer.
[0081] (5) An electron doping layer, an electron transport layer, and a metal electrode are disposed on the perovskite layer in a manner known in the art.
[0082] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.
[0083] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.
Claims
1. A method for preparing a large-area perovskite thin film layer, characterized in that, include: A perovskite precursor solution is coated onto the substrate surface to form a first precursor film. The first precursor film is pre-annealed to form a second precursor film containing fragmented crystals. The second precursor film containing fragmented crystals is subjected to pressure annealing to repair the grain boundaries caused by the fragmented crystals in the second precursor film. The pressure applied during the pressure annealing is 0.1-200 MPa and the pressure is perpendicular to the film plane of the second precursor film. The second precursor film is annealed while the pressure is applied.
2. The method for preparing a large-area perovskite thin film layer according to claim 1, characterized in that, include: After the first precursor film is formed, the first precursor film is dried and then subjected to the pre-annealing treatment.
3. The method for preparing a large-area perovskite thin film layer according to claim 1 or 2, characterized in that: The temperature for the pre-annealing treatment is 70-100℃.
4. The method for preparing a large-area perovskite thin film layer according to claim 1, characterized in that, Specifically, it includes: The pressure is applied to the second precursor film by a pressure plate, the pressure surface of which is a plane; wherein the pressure surface of the pressure plate is in direct contact with the second precursor film, or a liquid film is distributed between the pressure surface of the pressure plate and the second precursor film, the liquid film being formed by an inert solvent.
5. The method for preparing a large-area perovskite thin film layer according to claim 4, characterized in that: The pressure plate includes a polytetrafluoroethylene (PTFE) flat plate.
6. The method for preparing a large-area perovskite thin film layer according to claim 4, characterized in that: The inert solvent includes any one or more combinations of chlorobenzene, n-butanol, n-pentanol, or ethyl acetate.
7. The method for preparing a large-area perovskite thin film layer according to claim 1, characterized in that: The annealing process is performed at a temperature of 100-150℃ for 10-30 minutes.
8. A large-area perovskite thin film layer prepared by the method of any one of claims 1-7.
9. A photovoltaic device, comprising a first electrode, a first carrier transport layer, an active layer, a second carrier transport layer, and a second electrode arranged sequentially along a predetermined direction; characterized in that: The active layer includes the large-area perovskite thin film layer as described in claim 8.
10. The photovoltaic device according to claim 9, characterized in that, It also includes a first interface modification layer and / or a second interface modification layer, wherein the first interface modification layer is disposed between the first carrier transport layer and the active layer, and the second interface modification layer is disposed between the second carrier transport layer and the active layer.