Perovskite cell and preparation method thereof

Abstract

The invention provides a perovskite cell and a preparation method thereof, and belongs to the technical field of solar cells. The perovskite cell structure comprises a bottom electrode, a photoactive layer, an electron transport layer and a top electrode, the electron transport layer comprises a first film layer, a second film layer and an atomic layer deposition SnO2 layer, the first film layer material comprises at least one of C60 and derivatives thereof, and the second film layer material comprises at least one of C60 and derivatives thereof. And the material of the second film layer comprises at least one of hydroxylated fullerene, aminated fullerene and carboxylated fullerene. By introducing the fullerene functional layer, a nucleation site is provided for the initial stage of SnO2 deposition, the growth of the SnO2 layer is promoted, the shape-preserving compact SnO2 film is prepared, and the efficiency and the stability of a unijunction and laminated perovskite cell device can be effectively improved.

Description

Technical Field

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

[0002] Perovskite solar cells (PSCs) have attracted widespread attention due to their advantages such as diverse fabrication methods, tunable bandgap, high absorption coefficient, and long diffusion length, and are considered the most promising candidates for next-generation photovoltaic technology. A tandem perovskite solar cell consists of a bottom electrode, a top electrode, and multiple functional layers located between the two electrodes. These functional layers include a photoactive layer based on perovskite material and an electron transport layer (ETL).

[0003] The commonly used ETL is C 60 The / BCP structure combination has poor thermal stability (thermal decomposition at 300℃), is prone to moisture absorption, and has a loose and porous physical stacking, which can easily lead to degradation of the interface between the photoactive layer and the electrode and cannot effectively block external water and oxygen from eroding the photoactive layer material, seriously affecting the stability of PSCs. Summary of the Invention

[0004] In view of the technical problems existing in the background art, this application provides a perovskite solar cell and its preparation method, which can effectively improve the device efficiency and stability of single-junction and tandem perovskite solar cells.

[0005] In a first aspect, embodiments of this application provide a perovskite solar cell, comprising a bottom electrode, a photoactive layer, an electron transport layer, and a top electrode stacked from bottom to top. The electron transport layer comprises a first film layer, a second film layer, and an atomic layer deposited SnO2 layer stacked from bottom to top. The material of the first film layer includes C. 60 The second film layer comprises at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

[0006] Optionally, in some embodiments of this application, the material of the second film layer is selected from at least one of hydroxylated fullerenes, wherein the chemical formula of the hydroxylated fullerene is C2. 60 (OH) n , where n represents the number of hydroxyl groups, and n is selected from any positive integer.

[0007] Optionally, in some embodiments of this application, the average thickness of the first film layer is 10~20nm.

[0008] Optionally, in some embodiments of this application, the average thickness of the second film layer is 1~5 nm.

[0009] Optionally, in some embodiments of this application, the average thickness of the atomic layer deposited SnO2 layer is 10~30 nm.

[0010] Optionally, in some embodiments of this application, the total thickness of the first film layer, the second film layer, and the SnO2 layer deposited by the atomic layer is 21~55nm.

[0011] Optionally, in some embodiments of this application, the perovskite solar cell includes a hole transport layer disposed between the bottom electrode and the photoactive layer.

[0012] Optionally, in some embodiments of this application, the photoactive layer material is selected from at least one perovskite material.

[0013] Optionally, in some embodiments of this application, the perovskite solar cell includes a passivation layer disposed between the photoactive layer and the first film layer, wherein the material of the passivation layer is selected from one or more defect passivation materials such as ethylenediamine diiodide, propylenetriamine diiodide, piperazine, ethylenediamine, and p-fluorophenylethylamine hydrochloride.

[0014] Secondly, embodiments of this application provide a perovskite solar cell, comprising a bottom electrode, a first hole transport layer, a first photoactive layer, a first electron transport layer, a tunneling layer, a second hole transport layer, a second photoactive layer, a second electron transport layer, and a top electrode stacked from bottom to top. At least one of the first and second electron transport layers includes a first film layer, a second film layer, and an atomically deposited SnO2 layer stacked from bottom to top. The first film layer material includes C. 60 The second film layer comprises at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

[0015] Thirdly, embodiments of this application provide a method for preparing a perovskite solar cell, comprising the following steps: A functional film layer is fabricated on the bottom electrode; A top electrode is fabricated on the functional film layer; The preparation of the functional film layer includes: Deposited photoactive layer; The material of the first film layer is deposited on the photoactive layer to prepare the first film layer; The material for the second film layer is deposited on the first film layer to prepare the second film layer; An atomic layer deposition SnO2 layer was prepared on the second film layer using atomic layer deposition technology; Wherein, the first film material includes C 60The second film layer comprises at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

[0016] Optionally, in some embodiments of this application, a second film layer material is deposited on the first film layer, and the step of preparing the second film layer includes: The second film material is dispersed in an organic solvent to obtain a first solution; The first solution is deposited on the first film layer, and then annealed to prepare the second film layer.

[0017] Optionally, in some embodiments of this application, the concentration of the second film material in the first solution is 0.1~0.5 mg / mL.

[0018] Optionally, in some embodiments of this application, the organic solvent includes at least one of isopropanol, toluene, and chlorobenzene.

[0019] Optionally, in some embodiments of this application, the annealing temperature is 60~100℃ and the annealing time is 50~70s.

[0020] Optionally, in some embodiments of this application, the step of depositing a SnO2 layer on the second film layer using atomic layer deposition technology includes: Multiple atomic layer deposition cycles are repeated on the second film layer until the target thickness is reached to obtain a SnO2 layer. One of the steps of the atomic layer deposition cycle includes: introducing a tin source pulse for 0.1~0.3s, then introducing an inert gas purging for 2~10s, then introducing a deionized water pulse for 0.1~0.5s, followed by introducing the inert gas purging for 2~10s.

[0021] Optionally, in some embodiments of this application, the tin source includes at least one of tetra(dimethylamino)tin (IV), tetra(diethylamino)tin, and tin tetrachloride.

[0022] Optionally, in some embodiments of this application, the atomic layer deposition cycle is 150 to 300 times.

[0023] Optionally, in some embodiments of this application, the inert gas includes argon or nitrogen.

[0024] Fourthly, embodiments of this application provide a method for preparing a perovskite solar cell, comprising the following steps: A first hole transport layer, a first photoactive layer, a first electron transport layer, a tunneling layer, a second hole transport layer, a second photoactive layer, a second electron transport layer, and a top electrode are fabricated layer by layer on the bottom electrode. The fabrication steps of at least one of the first electron transport layer and the second electron transport layer include: Deposit the first film layer material to prepare the first film layer; A second film layer material is deposited on the first film layer to prepare the second film layer; A SnO2 layer is deposited on the second film layer using atomic layer deposition technology; Wherein, the first film material includes C 60 The second film material comprises at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

[0025] In the technical solution provided in this application, a first film layer / second film layer / SnO2 structure is used to replace C. 60 The / BCP structure, by inserting a fullerene film modified with active functional groups (-OH, -NH2, -COOH) between the first film layer and the atomic layer deposited SnO2 layer, provides a good growth substrate for the SnO2 layer deposition. This provides active sites for nucleation during the initial deposition stage, helps to eliminate the delayed growth problem of ALD islands, further improves the film formation effect, enhances the electrical performance of the atomic layer deposited SnO2 layer, improves the photoelectric performance of the battery, and further enhances the barrier ability and interfacial contact of the atomic layer deposited SnO2 layer, thereby improving the performance stability of the battery.

[0026] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of the perovskite solar cell proposed in the first embodiment of this application; Figure 2 This is a schematic diagram of the perovskite solar cell proposed in the second embodiment of this application; Figure 3 C 60 / SnO2 thin film and C 60 (OH) 14 / Comparison of AFM for SnO2 thin films; Figure 4 Hydroxylated fullerene (C 60 (OH) n Chemical structural formula; Figure 5 The perovskite solar cells prepared in Example 1 and Comparative Examples 1 to 5 JV curve.

[0029] Figure reference numerals: 100-Perovskite solar cell, 1-Bottom electrode, 2-Hole transport layer, 2a-First hole transport layer, 2b-Second hole transport layer, 3-Photoactive layer, 3a-First photoactive layer, 3b-Second photoactive layer, 4-Electron transport layer, 4a-First electron transport layer, 4b-Second electron transport layer, 41-First film layer, 42-Second film layer, 43-Atomic layer deposited SnO2 layer, 5-Top electrode, 6-Tunneling layer. Detailed Implementation

[0030] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0032] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0033] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0034] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0035] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0036] In the description of the embodiments of this application, the term "at least one" refers to one or more, "more than one" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0037] The commonly used ETL is C 60 The / BCP structure has poor thermal stability (it is prone to thermal decomposition at about 300℃), is hygroscopic, and physically accumulates, which can easily lead to degradation of the interface between the photoactive layer and the electrode and cannot effectively block the erosion of the photoactive layer material by external water and oxygen, seriously affecting the stability of single-junction and stacked PSCs.

[0038] Therefore, embodiments of this application provide a perovskite solar cell 100, which can be a single-junction cell or a stacked cell. For example, as Figure 1 As shown, in some embodiments, the perovskite solar cell 100 is a single-junction cell. The perovskite solar cell 100 device structure includes a bottom electrode 1, a photoactive layer 3, an electron transport layer 4, and a top electrode 5 stacked from bottom to top. The electron transport layer 4 includes a first film layer 41, a second film layer 42, and an atomic layer deposited SnO2 layer 43 stacked from bottom to top. The material of the first film layer 41 includes C. 60 At least one of its derivatives; the second film layer 42 material includes hydroxylated fullerene (C60 (OH) n Where n represents the number of hydroxyl groups, and n is selected from any positive integer, its structural formula is as follows: Figure 4 As shown), aminated fullerene (C 60 -NH2, molecular formula C 60 (NHCH2CH3)), carboxylated fullerene (COOH-C) 60 At least one of the following, wherein the atomic layer deposited SnO2 layer 43 refers to a thin film prepared by atomic layer deposition technology using SnO2 as the film material.

[0039] For example, in other embodiments, the perovskite solar cell 100 can also be a stacked solar cell, which can have several sub-cells. Each sub-cell's film structure includes a photoactive layer 3 and an electron transport layer 4. In at least one sub-cell, the electron transport layer 4 includes a first film layer 41, a second film layer 42, and an atomic layer deposited SnO2 layer, with the first film layer 41 located between the photoactive layer 3 and the second film layer 42. To better describe this structure, a stacked solar cell containing two sub-cells is taken as an example. Figure 2 As shown, the perovskite solar cell 100 includes a bottom electrode 1, a first hole transport layer 2a, a first photoactive layer 3a, a first electron transport layer 4a, a tunneling layer 6, a second hole transport layer 2b, a second photoactive layer 3b, a second electron transport layer 4b, and a top electrode 5, stacked from bottom to top. At least one of the first electron transport layer 4a and the second electron transport layer 4b includes a first film layer 41, a second film layer 42, and an atomic layer deposited SnO2 layer 43, stacked from bottom to top. The material of the first film layer 41 includes C. 60 The material of the second film layer 42 includes at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

[0040] In the technical solution provided in this application, a SnO2 layer 43 structure with a first film layer 41 / second film layer 42 / atomic layer deposition is used to replace C. 60 The / BCP structure has the following effects: (1) Replacing traditional BCP with SnO2, which has high chemical and thermal stability and strong barrier ability, can play the role of "built-in" barrier layer, effectively suppress the interface degradation and element diffusion between the photoactive layer and the electrode, improve the water and oxygen erosion problem, and thus improve the working stability of PSCs.

[0041] (2) The SnO2 layer is prepared by atomic layer deposition (ALD) technology. ALD film has the advantage of precise control of atomic thickness, which can grow ultra-thin and dense SnO2 layer in conformal manner, improve the film uniformity, further enhance the barrier ability and interfacial contact of SnO2 layer, and improve battery stability.

[0042] (3) Although ALD has better film-forming effect than other film-forming methods such as solution deposition, and is sufficient to prepare uniform and dense films, studies have found that the film-forming effect of ALD is affected by the substrate. When deposited on the surface of an inert substrate, it affects surface nucleation and makes it difficult to achieve ideal conformal growth. This is because the ALD precursor has weak adsorption on the inert substrate, causing the precursor to diffuse laterally on the substrate surface, forming island-like nuclei, which in turn leads to uneven film growth. In view of this, in the embodiments of this application, a fullerene film layer containing active functional groups (-OH, -NH2, -COOH) is inserted between the first film layer 41 and the atomic layer deposited SnO2 layer 43. This second film layer 42 can activate the surface of the first film layer 41, enhance the chemical interaction between the precursor and the substrate, and optimize the nucleation kinetics. Specifically, the second film layer 42 contains multiple active functional groups, which can provide active sites for nucleation during the initial deposition stage. The establishment of a covalent bonding pathway between the precursor and the second film layer 42 helps to eliminate the problem of delayed growth of ALD islands, further improves the film formation effect, enhances the electrical performance of the atomic layer deposited SnO2 layer 43, improves the photoelectric performance of the battery, and further enhances the barrier ability and interfacial contact of the atomic layer deposited SnO2 layer 43, thereby improving the working stability of the battery.

[0043] The material of the first film layer 41 includes C 60 At least one of the first film layer 41 and its derivatives can provide good electron transport performance. Together with the second film layer 42 and the atomic layer deposited SnO2 layer 43, they form an electron transport film layer with good electron transport performance, ensuring the photoelectric performance of the battery. If the first film layer 41 is removed, the only second film layer 42 and atomic layer deposited SnO2 layer 43 may not be sufficient to provide adequate electron transport, thus affecting the performance of the battery. Furthermore, in some embodiments, the material of the first film layer 41 is selected from C. 60 Compared to C 60 Derivatives, C 60 With superior electrophilicity, good electrical conductivity, and suitable band structure, it can be used in conjunction with SnO2 to construct electron transport films with excellent performance. Furthermore, compared to hydroxylated fullerenes, C... 60 The use of thermal evaporation deposition allows for better control of film thickness, thereby adjusting the electron transport properties of the film. Therefore, compared to other C... 60 Derivatives, such as PCBM, are more conducive to the construction of high-performance perovskite solar cells 100 together with the second film layer 42 and the atomic layer deposited SnO2 layer 43.

[0044] Furthermore, in some embodiments, the material of the second film layer 42 is selected from at least one of hydroxylated fullerenes. Hydroxylated fullerenes are readily available and have good activation effects. They also have good adsorption properties with water and tin precursors, which can better convert the ALD growth mode into a layer-by-layer deposition mode.

[0045] In some specific embodiments, the hydroxylated fullerene is selected from C 60 (OH)6, C 60 (OH) 12 C 60 (OH) 14 C 60 (OH) 16 C 60 (OH) 24 C 60 (OH) 88 At least one of them.

[0046] In some embodiments, the average thickness of the first film layer 41 is 10-20 nm; for example, it can be 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, or any two of the above values. In this application, "average thickness" can refer to the average thickness of the film or film layer at various locations. In actual testing, the thickness can be detected by a step tester or an atomic force microscope (AFM). Specifically, several test areas can be selected on the film or film layer (for example, the four corners and the middle area of ​​the film or film layer can be selected), and the thickness values ​​of the several areas can be measured by the atomic force microscope. Then, the average of the several thickness values ​​can be calculated to obtain the average thickness.

[0047] In some embodiments, the average thickness of the atomic layer deposited SnO2 layer 43 is 10~30nm; for example, it can be 10nm, 15nm, 20nm, 25nm, 30nm, or any two of the above values.

[0048] In some embodiments, the average thickness of the second film layer 42 is 1~5 nm; for example, it can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, or any two of the above values. Controlling it within this range helps to improve the photoelectric performance of the battery while improving the SnO2 film formation effect.

[0049] In some embodiments, the total thickness of the first film layer 41, the second film layer 42, and the atomic layer deposited SnO2 layer 43 is 21~55nm. For example, it can be 21nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, or any range between two of the above values.

[0050] The photoactive layer 3 can be made of photoactive layer materials commonly used in the art, such as at least one of commonly used perovskite materials. In some embodiments, the perovskite material can be a perovskite material with the general structural formula ABX3, where A is Cs. + 、Rb + [CH3N=NH] + CH3(CH2) n-2 NH3 + [NH3(CH2)] n NH3] 2+ At least one of the following, n≥2, B is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ At least one of them, X is selected from Cl - ,Br - I - At least one of them. The average thickness of the photoactive layer 3 can be 300~1000nm.

[0051] The material of the bottom electrode 1 may include, but is not limited to, at least one of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The average thickness of the bottom electrode 1 may be 100~200 nm.

[0052] The top electrode 5 is made of at least one metallic material, which may include, but is not limited to, one or more of Ag, Al, Cu, Mo, Au, Pt, and Ba. The average thickness of the top electrode 5 may be 100-200 nm.

[0053] In some embodiments, the perovskite solar cell 100 further includes a hole transport layer 2 disposed between the photoactive layer 3 and the bottom electrode 1. The material of the hole transport layer 2 may include, but is not limited to, at least one of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT / PSS), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). In some embodiments, the average thickness of the hole transport layer 2 may be 5-20 nm.

[0054] In addition, such as Figure 2 As shown, in some embodiments of this application, the perovskite solar cell 100 may further include a passivation layer disposed between the photoactive layer 3 and the first film layer 41, which helps to passivate surface defects of the photoactive layer 3, optimize the interface between the photoactive layer 3 and the first film layer 41, suppress nonradiative recombination of charge carriers, and help improve the photoelectric conversion efficiency (PCE) of the perovskite solar cell 100. The material of the passivation layer can be any defect passivation material commonly used in the art, such as one or more selected from, but not limited to, ethylenediamine diiodide, propylenetriamine diiodide, piperazine, ethylenediamine, and p-fluorophenylethylamine hydrochloride.

[0055] In some embodiments, the material of the tunneling layer 6 may include, but is not limited to, at least one of the following: a metal material, indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The metal material may include, but is not limited to, one or more of Ag, Al, Cu, Mo, Au, Pt, and Ba.

[0056] In some embodiments, the perovskite solar cell 100 may further include a substrate disposed below the bottom electrode 1 to support the aforementioned film structure. The substrate may include rigid or flexible substrates, specifically including glass, silicon wafers, polyamide, etc.

[0057] Furthermore, this application embodiment also provides a method for preparing a perovskite solar cell 100, which can prepare the perovskite solar cell 100 described above.

[0058] When the perovskite solar cell 100 to be prepared is a single-junction cell, the preparation method of the perovskite solar cell 100 includes the following steps: A functional film is deposited on the bottom electrode 1; A top electrode 5 is deposited on the functional film layer.

[0059] The preparation of the functional film layer includes: Preparation of photoactive layer 3; A first film layer 41 is deposited on the photoactive layer 3; A second film layer 42 is deposited on the first film layer 41; An atomic layer deposition SnO2 layer 43 is prepared on the second film layer 42 using atomic layer deposition technology; The material of the first film layer 41 includes C 60 The material of the second film layer 42 includes at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

[0060] The perovskite solar cell 100 described above can be prepared using the above method. This cell includes a bottom electrode 1, a functional film layer, and a top electrode 5 stacked sequentially. The functional film layer includes at least one sub-cell. Each sub-cell includes a photoactive layer 3 and an electron transport layer 4 stacked sequentially. The electron transport layer 4 includes a first film layer 41, a second film layer 42, and an atomic layer deposited SnO2 layer 43 stacked sequentially. The material of the first film layer 41 includes C. 60 At least one of the following: and its derivatives; the second film layer 42 material includes at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

[0061] In practice, the photoactive layer can be prepared on the surface of the previous film layer. For example, perovskite material can be deposited on the surface of the pretreated bottom electrode 1 (or hole transport layer) to form the photoactive layer.

[0062] It is understandable that the functional film layer can be prepared by sequentially preparing multiple film layers according to the stacking order of the target battery. When the battery is a single-junction battery, the functional film layer can be obtained by sequentially preparing the hole transport layer 2, the photoactive layer 3, the first film layer 41, the second film layer 42, and the atomic layer deposition SnO2 layer 43. For example, when the perovskite battery 100 also includes a passivation layer, the above steps, after preparing the photoactive layer 3, can further include: depositing a passivation material on the photoactive layer 3 to obtain the passivation layer. In this way, subsequent film layers are prepared on the surface of the passivation layer.

[0063] When the perovskite solar cell 100 to be prepared is a tandem solar cell, the preparation method of the perovskite solar cell 100 includes the following steps: A first hole transport layer 2a, a first photoactive layer 3a, a first electron transport layer 4a, a tunneling layer 6, a second hole transport layer 2b, a second photoactive layer 3b, a second electron transport layer 4b, and a top electrode 5 are fabricated layer by layer on the bottom electrode 1. The fabrication steps of at least one of the first electron transport layer 4a and the second electron transport layer 4b include: Deposit the material of the first film layer 41 to prepare the first film layer 41; The material of the second film layer 42 is deposited on the first film layer 41 to prepare the second film layer 42; An atomic layer deposition SnO2 layer 43 is deposited on the second film layer 42 using atomic layer deposition technology; The material of the first film layer 41 includes C 60 The material of the second film layer 42 includes at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

[0064] It is understandable that the battery can be fabricated sequentially according to the film layer stacking order of the target battery, which will not be elaborated here.

[0065] The second film layer 42 can be prepared by a solution method, which is simple and low-cost. Specifically, the step of depositing the second film layer 42 on the first film layer 41 may include: The material of the second film layer 42 is dispersed in an organic solvent to obtain a first solution; The first solution is deposited on the first film layer 41, and then annealed to prepare the second film layer 42.

[0066] In the first solution, the concentration of the second film layer 42 material is 0.1~0.5 mg / mL.

[0067] The organic solvent may include, but is not limited to, at least one of isopropanol, toluene, and chlorobenzene.

[0068] The annealing temperature can be 60~100℃, for example, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃, 95℃, 96℃, 97℃, 98℃, 99℃, 100℃, or any two of the above values; the annealing time can be 50~70s, for example, 50s, 55s, 60s, 65s, 70s, or any two of the above values. Annealing can optimize film quality.

[0069] The process of preparing an atomic layer deposited SnO2 layer 43 on the second film layer 42 using atomic layer deposition technology can be implemented through the following steps: S41, repeating multiple atomic layer deposition cycles on the second film layer 42 until the target thickness is reached to obtain the atomic layer deposited SnO2 layer 43.

[0070] One of the atomic layer deposition cycle steps includes: introducing a tin source pulse for 0.1~0.3s, then introducing an inert gas purging for 2~10s, then introducing a deionized water pulse for 0.1~0.5s, followed by introducing the inert gas purging for 2~10s.

[0071] In some embodiments of this application, the tin source includes, but is not limited to, at least one of tetra(dimethylamino)tin (IV), tetra(diethylamino)tin, and tin tetrachloride. The inert gas may include, but is not limited to, argon or nitrogen.

[0072] In addition, in some embodiments, the number of atomic layer deposition cycles is 150 to 280. By adjusting the number of cycles, the thickness of the atomic layer deposited SnO2 layer 43 can be precisely controlled.

[0073] Furthermore, the first film layer 41, hole transport layer 2, photoactive layer 3, bottom electrode 1, top electrode 5, passivation layer, and tunneling layer 6 can be prepared using methods commonly used in the art, such as chemical vapor deposition, electrolytic deposition, co-precipitation, thermal evaporation coating (CVD), electron beam evaporation coating, magnetron sputtering, physical vapor deposition (PVD), atomic layer deposition, spin coating, printing, inkjet printing, blade coating, dip-coating, etc. This application does not impose any limitations on these methods.

[0074] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0075] Example 1 This embodiment proposes an inverted perovskite solar cell with the following structure: ITO / PEDOT: PSS / Cs 0.2 FA 0.8 Pb 0.5 Sn 0.5 I3 / C 60 / C 60 (OH) 14 / ALD SnO2 / Ag.

[0076] The battery manufacturing method in this embodiment specifically includes the following steps: (1) Substrate pretreatment: The pre-patterned ITO conductive glass substrate was ultrasonically cleaned for 30 minutes each with detergent, ultrapure water, isopropanol and anhydrous ethanol.

[0077] (2) Preparation of hole transport layer: PEDOT:PSS solution (diluted with isopropanol at a volume ratio of 1:5) was spin-coated on the ITO surface at 2000 rpm for 30 seconds, and then annealed at 100°C in air for 20 minutes to obtain hole transport layer.

[0078] (3) Preparation of the photoactive layer: (3.1) Preparation of perovskite precursor solution: CsI, formamidinium iodide (FAI), SnI2 and PbI2 were dissolved in a mixed solvent of DMF and DMSO (volume ratio of DMF to DMSO was 3:1) according to the molar ratio of Cs:FA:Pb:Sn = 0.2:0.8:0.5:0.5 to prepare a perovskite precursor solution. 0.2 FA 0.8 Pb 0.5 Sn 0.5 A perovskite solution with an I3 concentration of 2 mol / L was prepared. Tin powder, methylamine thiocyanate (MASCN), and SnF2 were added to the narrow bandgap perovskite solution at concentrations of 6 mg / ml tin powder, 3 mg / ml MASCN, and 10 mg / ml SnF2. The mixture was stirred overnight and then filtered through a 0.22 mm PTFE membrane before use to obtain the perovskite precursor solution.

[0079] (3.2) Preparation of photoactive layer: The substrate was transferred to a nitrogen glove box, and a perovskite precursor solution was spin-coated onto the hole transport layer at 4000 rpm for 10 seconds to obtain a wet film. Subsequently, the wet film was immediately transferred into a vacuum chamber and treated under a vacuum of about 3 Pa for 25 seconds, and then annealed at 120°C for 1 minute in a nitrogen atmosphere.

[0080] (4) Preparation of the first film layer: A 15 nm thick C film was thermally evaporated and deposited on the surface of the photoactive layer. 60 Layer (rate 0.9 angstroms / second).

[0081] (5) Preparation of the second film layer: Fullerene C is spin-coated on the surface of the first film layer. 60 (OH) 14 The solution (0.3 mg / mL, isopropanol solvent) was spin-coated at 5000 rpm for 30 seconds and heated at 85°C for 60 seconds to obtain a second film with a thickness of approximately 2 nm.

[0082] (6) SnO2 layer preparation: The wafer obtained in step (5) was transferred into an atomic layer deposition system (Kemicro) to deposit a SnO2 layer with a thickness of 20 nm. The precursor was tetratetra(dimethylamino)tin(IV) (purity 99.9999%) and deionized water. Tin source pulse / purge: 0.122 s / 6 s (nitrogen flow rate 20 standard mL / min). Water pulse / purge: 0.2 s / 6 s (nitrogen flow rate 20 standard mL / min).

[0083] (7) Top electrode preparation: The device obtained in step (6) is transferred to the substrate of the vapor deposition apparatus. In the vacuum vapor deposition apparatus, Ag with a thickness of about 150 nm is vapor deposited on the SnO2 layer (rate 1 Å / s) to obtain a complete perovskite solar cell.

[0084] Example 2 The scheme in this embodiment is basically the same as that in embodiment 1, except that the thickness of the second film layer is 1 nm in this embodiment.

[0085] Example 3 The scheme in this embodiment is basically the same as that in embodiment 1, except that the thickness of the second film layer is 5nm in this embodiment.

[0086] Example 4 The scheme in this embodiment is basically the same as that in embodiment 1, except that the thickness of the second film layer is 8nm in this embodiment.

[0087] Example 5 This embodiment is basically the same as Embodiment 1, except that the material of the second film layer is C in this embodiment. 60 (OH) 24 .

[0088] Example 6 The scheme in this embodiment is basically the same as that in Embodiment 1, except that the material of the first film layer is a C60 derivative PCBM, and the corresponding battery structure is: ITO / PEDOT: PSS / Cs. 0.2 FA 0.8 Pb 0.5 Sn 0.5 I3 / PCBM / C 60 (OH) 14 / ALD SnO2 / Ag.

[0089] The structure of PCBM is as follows:

[0090] Example 7 The scheme in this embodiment is basically the same as that in Embodiment 1, except that the material of the first film layer is the C60 derivative CPMAC, and the corresponding battery structure is: ITO / PEDOT: PSS / Cs. 0.2 FA 0.8 Pb 0.5 Sn 0.5 I3 / CPMAC / C 60 (OH) 14 / ALD SnO2 / Ag.

[0091] The structure of CPMAC is as follows:

[0092] Comparative Example 1 This comparative example is basically the same as Example 1, except that there is no second film layer in this comparative example, and the SnO2 layer is prepared on the surface of the first film layer.

[0093] Comparative Example 2 This comparative example is basically the same as Example 1, except that the SnO2 layer is replaced with a BCP layer. Correspondingly, step (6) is changed to: transferring the device obtained in step (5) onto the substrate of the evaporator, and then, in the vacuum evaporator, at C... 60 The BCP with a thickness of approximately 10 nm was deposited on the layer (at a rate of 0.8 Å / s).

[0094] Comparative Example 3 The comparative example scheme is basically the same as that of Example 1, except that the SnO2 layer is replaced with a TiO2 layer. Accordingly, step (6) is changed to: TiO2 layer preparation: the wafer obtained in step (5) is transferred into an atomic layer deposition system (Kemicro) to deposit a TiO2 layer with a thickness of 20 nm. The precursor is titanium tetraisopropoxide and deionized water. Titanium source pulse / purge: 0.1 sec / 6 sec (nitrogen flow rate 20 standard mL / min). Water pulse / purge: 0.2 sec / 6 sec (nitrogen flow rate 20 standard mL / min).

[0095] Comparative Example 4 This comparative example is basically the same as Example 1, except that in this comparative example, the material of the second film layer is C. 60 (OH) 14 Replace with PCBM. Accordingly, step (5) is changed to: Preparation of the second film: PCBM solution (10 mg / mL, isopropanol solvent) was spin-coated onto the surface of the first film at 5000 rpm for 30 seconds, and then heated at 85°C for 60 seconds to obtain a second film with a thickness of approximately 5 nm.

[0096] Comparative Example 5 This comparative example is basically the same as Example 1, except that there is no first film layer in this comparative example. During preparation, it was found that C... 60 (OH) 14 Its dispersibility in nonpolar solvents is too poor, and the C2000 can be formulated. 60 (OH) 14 The highest concentration of the solution can only reach 10 mg / mL, based on which the maximum thickness of the second film layer is about 8 nm.

[0097] Experimental Example (1) Surface Roughness Detection Following the preparation steps of the first film layer, the second film layer, and the SnO2 layer in Example 1, C was prepared on a polished Si wafer. 60 Layer, C 60 / SnO2 layer (ALD, 50 cycle), C 60 (OH) 14 Layer, C 60 (OH) 14 / SnO2 layer (ALD, 50 cycles). The above film was scanned using atomic force microscopy (AFM) to obtain the root mean square roughness (RMS), and the results are as follows. Figure 3 .

[0098] As can be seen from the figure, after depositing the SnO2 layer, C 60 The RMS of the layer is 1.8 nm, while C 60 (OH) 14 The RMS value of the layer is 0.9 nm, indicating that the ALD SnO2 film has good performance in active C 60 (OH) 14 The growth on the substrate is a layered, uniform growth, with no delayed nucleation.

[0099] Experimental Example (II) Device Performance Testing The perovskite solar cells prepared in Examples 1 to 7 and Comparative Examples 1 to 5 were tested using a solar simulator, and the current density-voltage (DC-V) curves of the cells were plotted. JV The curve is used to obtain the open-circuit voltage of the battery. V oc and photoelectric conversion efficiency (PCE). The results are recorded in Table 1 and Figure 5 In the figure, the horizontal axis represents voltage, and the vertical axis represents current density.

[0100] Table 1

[0101] Results analysis: Compared to the battery in Comparative Example 1, the battery prepared in Example 1 has higher PCE and open-circuit voltage, indicating that modifying the battery with a second film layer containing active functional groups between the first film layer and the atomic layer deposited SnO2 layer helps to improve the photoelectric performance of the battery. Compared to the batteries in Comparative Examples 2 and 3, the battery prepared in Example 1 has a higher current density at the same voltage, indicating that ALD-SnO2 has better compatibility with the second film layer than BCP or TiO2 layer, which is more conducive to improving the photoelectric performance of the battery.

[0102] The photoelectric performance of the battery in Comparative Example 4 was significantly worse than that of the battery in Example 1, indicating that PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) as an intermediate layer could not bring any benefit to ALD-SnO2 deposition. This may be because PCBM does not have active functional groups and cannot provide active sites for nucleus formation in the initial deposition stage, thus eliminating the problem of delayed growth of ALD islands.

[0103] Comparative Example 5 battery did not exhibit photoelectric properties, which may be due to the high concentration of C. 60 (OH) 14 The uniformity of the solution-prepared film is extremely poor and the thickness is thin, making it difficult to achieve electron transport properties.

[0104] The cells in Examples 1 to 7 all exhibit higher PCE and open-circuit voltage, indicating that the perovskite cells proposed in this application have excellent photoelectric performance. Furthermore, overall, the photoelectric performance of Examples 1 to 3 is better than that of Example 4, indicating that controlling the thickness of the second film layer within the range of 1 to 5 nm is more conducive to improving photoelectric performance. This may be because when the thickness of the second film layer is too thick, its film uniformity will deteriorate, which is not conducive to carrier transport, and the gain effect on ALD-SnO2 deposition will also decrease. In addition, the photoelectric performance of Example 1 is better than that of Examples 6 and 7, indicating that controlling the combination of C60 / hydroxylated fullerene / atomic layer deposition SnO2 layer is more conducive to obtaining cells with high photoelectric performance than using fullerene derivatives.

[0105] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A perovskite solar cell, characterized in that, The structure includes a bottom electrode, a photoactive layer, an electron transport layer, and a top electrode stacked from bottom to top. The electron transport layer includes a first film layer, a second film layer, and an atomic layer-deposited SnO2 layer stacked from bottom to top. The material of the first film layer includes C. 60 The second film layer comprises at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

2. The perovskite solar cell according to claim 1, characterized in that, The second film material is selected from at least one hydroxylated fullerene, wherein the general chemical formula of the hydroxylated fullerene is C2. 60 (OH) n , where n represents the number of hydroxyl groups, and n is selected from any positive integer.

3. The perovskite solar cell according to claim 1, characterized in that, The perovskite solar cell has at least one of the following characteristics: (1) The average thickness of the first film layer is 10~20nm; (2) The average thickness of the second film layer is 1~5 nm; (3) The average thickness of the atomic layer deposited SnO2 layer is 10~30 nm; (4) The total thickness of the first film layer, the second film layer and the atomic layer deposited SnO2 layer is 21~55nm; (5) The perovskite solar cell includes a hole transport layer, which is disposed between the bottom electrode and the photoactive layer; (6) The material of the photoactive layer is selected from at least one perovskite material; (7) The perovskite solar cell includes a passivation layer disposed between the photoactive layer and the first film layer, wherein the material of the passivation layer is selected from one or more of ethylenediamine diiodide, propylenetriamine diiodide, piperazine, ethylenediamine, and p-fluorophenylethylamine hydrochloride.

4. A perovskite battery, characterized in that, The structure includes, from bottom to top, a bottom electrode, a first hole transport layer, a first photoactive layer, a first electron transport layer, a tunneling layer, a second hole transport layer, a second photoactive layer, a second electron transport layer, and a top electrode. At least one of the first and second electron transport layers includes, from bottom to top, a first film layer, a second film layer, and an atomically deposited SnO2 layer. The material of the first film layer includes C. 60 The second film layer comprises at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

5. A method for preparing a perovskite solar cell, characterized in that, Includes the following steps: Deposit a functional film on the bottom electrode; A top electrode is deposited on the functional film layer; The preparation of the functional film layer includes: Preparation of photoactive layer; A first film layer is deposited on the photoactive layer; A second film layer is deposited on the first film layer; An atomic layer deposition SnO2 layer was prepared on the second film layer using atomic layer deposition technology; The material of the first film layer includes C 60 The second film layer comprises at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that, The step of depositing a second film layer on the first film layer includes: The material of the second film layer is dispersed in an organic solvent to obtain a first solution; The first solution is deposited on the first film layer, and then annealed to prepare the second film layer.

7. The method for preparing a perovskite solar cell according to claim 6, characterized in that, In the first solution, the concentration of the material in the second membrane layer is 0.1~0.5 mg / mL; and / or, The organic solvent includes at least one of isopropanol, toluene, and chlorobenzene; and / or, The annealing temperature is 60~100℃, and the annealing time is 50~70s.

8. The method for preparing a perovskite solar cell according to claim 5, characterized in that, The steps for preparing an atomic layer deposited SnO2 layer on the second film layer using atomic layer deposition technology include: Multiple atomic layer deposition cycles are repeated on the second film layer until the target thickness is reached to obtain an atomic layer deposited SnO2 layer. One of the steps of the atomic layer deposition cycle includes: introducing a tin source pulse for 0.1~0.3s, then introducing an inert gas purging for 2~10s, then introducing a deionized water pulse for 0.1~0.5s, followed by introducing the inert gas purging for 2~10s.

9. The method for preparing a perovskite solar cell according to claim 8, characterized in that, The tin source includes at least one of tetra(dimethylamino)tin (IV), tetra(diethylamino)tin, and tin tetrachloride; and / or, The atomic layer deposition cycle is 150-300 times; and / or, The inert gas includes argon or nitrogen.

10. A method for preparing a perovskite solar cell, characterized in that, Includes the following steps: A first hole transport layer, a first photoactive layer, a first electron transport layer, a tunneling layer, a second hole transport layer, a second photoactive layer, a second electron transport layer, and a top electrode are fabricated layer by layer on the bottom electrode. The fabrication steps of at least one of the first electron transport layer and the second electron transport layer include: The material for depositing the first film layer is used to prepare the first film layer; The material for the second film layer is deposited on the first film layer to prepare the second film layer; An atomic layer SnO2 layer is deposited on the second film layer using atomic layer deposition technology; The material of the first film layer includes C 60 The second film layer comprises at least one of hydroxylated fullerene, aminolated fullerene, and carboxylated fullerene.

Images