Perovskite solar cell and preparation method and application thereof

Abstract

This invention discloses a perovskite solar cell, its preparation method, and its application, belonging to the field of photovoltaic technology. The perovskite solar cell provided by this invention includes a transparent electrode, a composite hole transport structure, a perovskite absorber layer, an electron transport layer, and a metal electrode sequentially stacked. The composite hole transport structure includes a nickel oxide layer and a SAM organic modification layer stacked starting from the transparent electrode. The raw materials for preparing the SAM organic modification layer include a mixture of Me-4PACz and Br-4PACz in a molar ratio of 0.25 to 10:1. The perovskite solar cell provided by this invention can effectively improve its PCE and VE. OC FF and J SC Technical parameters, etc. This invention also provides a method for preparing the above-mentioned perovskite solar cells and their applications.

Description

Technical Field

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

[0002] With the rapid advancement of technology, human society's demand for energy is increasing daily. However, traditional fossil fuel reserves are limited, and their use pollutes the environment, restricting their further development. Therefore, developing new clean and renewable energy sources has become an urgent task. In the process of developing renewable energy, solar cells, as a sustainable and clean energy conversion technology, have received widespread attention. Among various types of solar cells, perovskite solar cells (PSCs) have made significant progress in recent years. Thanks to their excellent photovoltaic performance and low cost, PSCs are considered one of the main competitors in the next-generation photovoltaic industry. Among them, inverted structure PSCs have become a research hotspot due to their superior process, low hysteresis effect, and high stability. Currently, the highest certified efficiency of inverted PSCs has exceeded 26.7%, surpassing that of traditional structure PSCs.

[0003] The rapid development of inverse power conversion sensors (PSCs) benefits from in-depth research into the mechanisms of their key materials. In PSCs, research on transport layer materials and their mechanisms of action is crucial for improving device power conversion efficiency (PCE). Research on transport layer materials not only focuses on their intrinsic transport properties but also includes suppressing interfacial transport losses, thus often involving the regulation of multiple complex mechanisms and processes.

[0004] Because inverted PSCs employ a pin structure, the hole transport layer (HTL) is buried within the perovskite layer as the lower interface and participates in the light absorption process of the perovskite thin film. Therefore, compared to the upper electron transport layer (ETL), the HTL has a more critical impact on the photovoltaic performance of the device. Although various HTLs exist, such as organic molecules or polymers (PTAA), metal oxide semiconductors (NiO2), etc., are also used. X High-efficiency transport layers (HTLs) such as self-assembled monolayers (SAMs) have been designed and widely used to meet the basic requirements for hole transport. However, these HTLs still have significant problems in long-term stability, intrinsic carrier extraction, and high-efficiency PCE applications. These problems hinder the further application of HTLs and restrict the development of high-efficiency inverse PSCs. Therefore, developing a highly reliable and adaptable high-efficiency transport HTL is of great significance for the long-term development of inverse PSCs. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a perovskite solar cell that can effectively improve its PCE (conversion efficiency) and VE. OC (Open circuit voltage), FF (fill factor), and JSC Technical parameters such as (short-circuit current) have been improved; the technical problems of high energy loss and low hole transmission efficiency at the hole transport layer interface have been solved in related technologies.

[0006] The present invention also provides a method for preparing the above-mentioned perovskite solar cell.

[0007] This invention also provides applications of the aforementioned perovskite solar cells.

[0008] According to an embodiment of a first aspect of the present invention, a perovskite solar cell is provided, the perovskite solar cell comprising a transparent electrode, a composite hole transport structure, a perovskite absorber layer, an electron transport layer and a metal electrode stacked sequentially; the composite hole transport structure comprises a nickel oxide layer and a SAM organic modification layer stacked starting from the transparent electrode;

[0009] The raw materials for preparing the SAM organic modification layer include a mixture of Me-4PACz ([4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid, CAS: 2747959-96-0) and Br-4PACz ([4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphonic acid; CAS: 2996161-28-3) in a molar ratio of 0.25 to 10:1.

[0010] The perovskite solar cell according to embodiments of the present invention has at least the following beneficial effects:

[0011] In inverted perovskite solar cells, interfacial carrier transport has a significant impact on device performance. Therefore, this invention introduces a modification material (SAM organic modification layer) to achieve interfacial passivation and reduce interfacial transport losses.

[0012] The composite hole transport structure employed in this invention utilizes the structural characteristics of nickel oxide layer—its transport stability, dense coverage, and uniform anchoring—while simultaneously loading a bimolecular SAM organic modification layer with interface bandgap modulation. Through the synergistic effect of the nickel oxide layer and the SAM organic modification layer, good contact and stable hole transport between the composite hole structure and the bottom transparent electrode are ensured. Furthermore, energy level matching and defect passivation are achieved between the perovskite absorber layer and the composite hole transport structure, providing additional hole extraction enhancement and recombination loss suppression for interface transport. Therefore, the resulting composite hole transport structure effectively improves hole transport efficiency while also possessing advantages such as good stability and simple fabrication.

[0013] SAM molecules typically possess two main parts: anchoring groups and functional groups. The anchoring groups enable SAM molecules to bind to the surface hydroxyl groups (-OH) of the oxide (nickel oxide layer), achieving self-assembly on the oxide surface. The functional groups provide functions such as hole transport and enhanced wettability. The self-assembly, anchoring, and structurally tunable characteristics of SAM give it broad application prospects. It can be used alone as a hole transport material or as a surface modification of oxides, offering advantages such as simple preparation and excellent performance. In the perovskite solar cell provided by this invention, due to the selection of a specially formulated and proportioned SAM organic modification layer, it not only stabilizes the nickel oxide layer structure but also makes the band structure of the composite hole transport structure tunable. This is more conducive to energy level matching with the perovskite absorber layer, avoiding energy loss caused by energy level mismatch; ultimately improving the overall performance of the perovskite solar cell.

[0014] According to some embodiments of the present invention, the perovskite solar cell further includes a transparent substrate disposed on the side of the transparent electrode away from the composite hole transport structure. Industrially, for ease of manufacturing and transportation, the transparent substrate and the transparent electrode are typically composited into a single integral component, such as a single piece of ITO glass; the ITO layer in the ITO glass is fabricated using magnetron sputtering; wherein the transparent electrode serves as the positive electrode.

[0015] According to some embodiments of the present invention, the nickel oxide layer includes nickel oxide (NiO). X The nickel oxide nanoparticles have a cubic lattice structure.

[0016] Inorganic NiO X Due to the non-stoichiometric coordination environment of its preparation process, it contains multiple components composed of Ni in different valence states, such as NiO, NiOOH, Ni(OH)2, and Ni ≥3+ These components facilitate hole transport in the nickel oxide layer. Additionally, NiO... X The surface hydroxyl groups (-OH) of NiO also make it a good anchoring site for specific groups. Meanwhile, NiO X It also has advantages such as low-temperature processing, low cost, and good stability.

[0017] According to some embodiments of the present invention, the thickness of the nickel oxide layer is 25–35 nm. For example, it can be approximately 30 nm.

[0018] According to some embodiments of the present invention, the molar ratio of Me-4PACz to Br-4PACz is 0.25 to 9:1. For example, it can be about 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1 or about 8:1.

[0019] According to some embodiments of the present invention, the molar ratio of Me-4PACz to Br-4PACz is 8 to 10:1. For example, it can be approximately 9:1.

[0020] By adjusting the above ratios, the composite hole transport structure can have different band structures, and can further adapt to different perovskite absorber layers, which is more conducive to the interface transport between the perovskite absorber layer and the composite hole transport structure.

[0021] According to some embodiments of the present invention, the thickness of the SAM organic modification layer is 0.5 to 1.5 nm. For example, it can be about 1 nm. In practice, the organic modification layer is usually a molecular layer of at least several layers, and its thickness is difficult to measure effectively. The thickness is calculated based on the amount of raw materials used in the preparation of the SAM organic modification layer.

[0022] According to some embodiments of the present invention, the material of the perovskite absorber layer has the general formula (Cs) x FA y MA 1-x-y )Pb(I z Br 3-z ).

[0023] According to some embodiments of the present invention, the perovskite absorber layer comprises at least one of highly efficient anti-solvent perovskite, highly efficient non-anti-solvent perovskite, and wide-bandgap perovskite (bandgap 1.85 eV).

[0024] The highly efficient antisolvent perovskite is represented by Cs. 0.05 FA 0.85 MA 0.1 PbI3.

[0025] The high-efficiency, non-reactive solvent perovskite material is represented by Cs. 0.17 FA 0.83 PbI3.

[0026] The wide-bandgap perovskite is represented by Cs. 0.2 FA 0.8 PbI 1.5 Br 1.5 .

[0027] In actual production, the subscripts in the chemical formula of the above materials can change according to the feeding ratio, and thus the efficiency of perovskite will change accordingly.

[0028] According to some embodiments of the present invention, the material of the perovskite absorber layer includes Cs. 0.05 FA 0.85 MA 0.1 PbI3, Cs 0.17 FA 0.83PbI3 and Cs 0.2 FA 0.8 PbI 1.5 Br 1.5 At least one of them. Specifically,

[0029] When the material of the perovskite absorber layer is Cs 0.05 FA 0.85 MA 0.1 When using PbI3, the molar ratio of Me-4PACz to Br-4PACz in the SAM organic modification layer is 4 to 10:1. For example, it can be approximately 5:1, 6:1, 8:1, or approximately 9:1.

[0030] When the material of the perovskite absorber layer is Cs 0.17 FA 0.83 When PbI3 is used, the molar ratio of Me-4PACz to Br-4PACz in the SAM organic modification layer is 3.5 to 4.5:1.

[0031] When the material of the perovskite absorber layer is Cs 0.2 FA 0.8 PbI 1.5 Br 1.5 At that time, the molar ratio of Me-4PACz and Br-4PACz in the SAM organic modification layer was 0.8 to 1.2:1.

[0032] According to some embodiments of the present invention, the thickness of the perovskite absorber layer is 700–750 nm. For example, it can be approximately 720 nm or approximately 730 nm.

[0033] According to some embodiments of the present invention, the perovskite solar cell further includes an upper surface passivation layer disposed between the perovskite absorber layer and the electron transport layer.

[0034] According to some embodiments of the present invention, the material of the upper surface passivation layer includes piperazine monoiodine (PI, CAS: 56310-12-4). The upper surface passivation layer is generally considered to be embedded in the perovskite active layer, with negligible thickness.

[0035] According to some embodiments of the present invention, the electron transport layer is made of fullerene (C... 60 At least one of the following: (CAS: 99685-96-8) and BCP (CAS: 4733-39-5).

[0036] According to some embodiments of the present invention, the electron transport layer comprises a fullerene layer and a copper bath layer stacked thereon. The fullerene layer has a thickness of 35–45 nm; specifically, it can be about 40 nm. The copper bath layer has a thickness of 5–10 nm; specifically, it can be about 8 nm.

[0037] According to some embodiments of the present invention, the perovskite solar cell further includes a hole blocking layer disposed between the electron transport layer and the metal electrode.

[0038] According to some embodiments of the present invention, the metal electrode is made of copper (serving as the negative electrode).

[0039] According to some embodiments of the present invention, the thickness of the metal electrode is 80–120 nm. For example, it can be approximately 100 nm.

[0040] According to an embodiment of a second aspect of the present invention, a method for fabricating the perovskite solar cell described above is provided, the method comprising the following steps:

[0041] S1. The nickel oxide layer is formed on the surface of the transparent electrode;

[0042] S2. The SAM organic modification layer is formed on the surface of the nickel oxide layer;

[0043] S3. The perovskite absorber layer, electron transport layer and metal electrode are sequentially disposed on the surface of the SAM organic modification layer.

[0044] Since the preparation method employs all the technical solutions of the perovskite solar cells described in the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments. Furthermore,

[0045] The preparation method provided by this invention has the advantages of being simple, easy to implement, and convenient to operate. It can promote the large-scale production of perovskite solar cells and has good application prospects.

[0046] According to some embodiments of the present invention, in step S1, the nickel oxide layer is formed by sequentially performing a first spin coating and a first annealing.

[0047] According to some embodiments of the present invention, the first spin coating method includes at least one of dynamic spin coating and static spin coating. Static spin coating is preferred.

[0048] According to some embodiments of the present invention, the slurry used for the first spin coating is a nickel oxide dispersion, and the solvent of the nickel oxide dispersion includes water.

[0049] According to some embodiments of the present invention, the solvent of the nickel oxide dispersion is a mixture of water and isopropanol.

[0050] According to some embodiments of the present invention, the volume ratio of water to isopropanol in the solvent of the nickel oxide dispersion is 3 to 5:1; for example, it can be about 3.5:1, 4:1 or about 4.5:1.

[0051] According to some embodiments of the present invention, the concentration of the nickel oxide dispersion is 5–15 mg / mL; specifically, it can be about 8 mg / mL, 10 mg / mL, or about 12 mg / mL. In the first spin coating, this concentration will affect the thickness of the nickel oxide layer to some extent, and this thickness will affect the hole transport efficiency of the nickel oxide layer; within this concentration range, the hole transport capability is unrestricted and will not obstruct the incidence of sunlight.

[0052] According to some embodiments of the present invention, in the first spin coating, the amount of nickel oxide dispersion used is 25–45 μL / cm. 2 For example, it could be approximately 30 μL / cm. 2 35μL / cm 2 or approximately 40 μL / cm 2 .

[0053] According to some embodiments of the present invention, the rotation speed of the first spin coating is 3000 to 4000 rpm. For example, it can be about 3500 rpm. Within this rotation speed, the thickness uniformity of the nickel oxide layer can be improved, and the nickel oxide layer can have a suitable thickness.

[0054] According to some embodiments of the present invention, the duration of the first spin coating is 30 to 50 seconds. For example, it can be approximately 35 seconds, 40 seconds, or approximately 45 seconds.

[0055] According to some embodiments of the present invention, the temperature of the first annealing is 105–115°C. For example, it can be approximately 100°C.

[0056] According to some embodiments of the present invention, the duration of the first annealing is 10 to 15 minutes. For example, it can be approximately 12 minutes or approximately 13 minutes.

[0057] According to some embodiments of the present invention, in step S2, the SAM organic modification layer is formed by sequentially performing a second spin coating and a second annealing.

[0058] This invention forms a composite hole transport structure through two spin coating processes, which enables the two molecules in the SAM organic modification layer to self-assemble and anchor onto the inorganic transport layer. It has the advantages of simple method and high repeatability.

[0059] According to some embodiments of the present invention, the second spin coating method includes at least one of dynamic spin coating and static spin coating. Static spin coating is preferred.

[0060] According to some embodiments of the present invention, the solvent in the slurry used for the second spin coating is at least one selected from alcohol solvents, DMF, and DMSO; the solute is Me-4PACz and Br-4PACz. The alcohol solvent includes at least one selected from isopropanol (IPA), methanol, and ethanol.

[0061] According to some embodiments of the present invention, the concentration of solute in the slurry used for the second spin coating is 0.8 to 1.5 mmol / L. For example, it can be about 1 mmol / L or about 1.2 mmol / L.

[0062] According to some embodiments of the present invention, in the second spin coating, the amount of slurry used is 25–45 μL / cm. 2 For example, it could be approximately 30 μL / cm. 2 35μL / cm 2 or approximately 40 μL / cm 2 According to some embodiments of the present invention, the rotation speed of the second spin coating is 3000 to 5000 rpm. For example, it can be approximately 4000 rpm.

[0063] According to some embodiments of the present invention, the duration of the second spin coating is 25 to 35 seconds. For example, it can be approximately 30 seconds.

[0064] Similar to the first spin coating, the concentration of the slurry, the spin speed, and the duration of the second spin coating all serve to adjust the thickness and uniformity of the SAM organic modification layer.

[0065] According to some embodiments of the present invention, the temperature of the second annealing is 100-110°C. For example, it can be about 105°C.

[0066] According to some embodiments of the present invention, the duration of the second annealing is 10 to 15 minutes. For example, it can be approximately 12 minutes.

[0067] According to some embodiments of the present invention, in step S3, the setting of the perovskite active layer includes the following steps:

[0068] According to the stoichiometric ratio of ABX3, AX and BX2 are mixed in an organic solvent to obtain a perovskite precursor slurry.

[0069] The perovskite precursor slurry was spin-coated onto the surface of the composite hole transport structure and then subjected to a third annealing.

[0070] in,

[0071] AX includes at least one of MACl, CsI, MAI, and FAI;

[0072] BX2 includes at least one of PbI2, PbCl2, and PbBr2.

[0073] The choice between AX and BX2, and the amount to be added, depends on the target material of the perovskite active layer.

[0074] Due to the possibility of errors in material feeding, it is acceptable for the subscript values ​​in the chemical formula of the perovskite active layer to deviate within ±2%.

[0075] The organic solvent is a mixture of DMF and DMSO. The volume ratio of DMF to DMSO is 3 to 5:1; for example, it can be about 3.5:1, 4:1 or about 4.5:1.

[0076] The concentration of the perovskite precursor slurry, calculated according to ABX3, is 1–2 mol / L; specifically, it can be about 1.2 mol / L, 1.5 mol / L, 1.6 mol / L, or about 1.8 mol / L.

[0077] The spin-coating amount of the precursor slurry is 25–45 μL / cm. 2 For example, it could be approximately 30 μL / cm. 2 35μL / cm 2 or approximately 40 μL / cm 2 L / cm 2 For example, it could be approximately 60 μL / cm. 2 70μL / cm 2 80μL / cm 2 or approximately 90 μL / cm 2 .

[0078] The temperature for the third annealing is 90–160°C. For example, it can be approximately 100°C, 110°C, 140°C, or approximately 150°C.

[0079] The duration of the third annealing is 10–35 minutes. For example, it can be approximately 15 minutes, 20 minutes, 25 minutes, or approximately 30 minutes.

[0080] According to some embodiments of the present invention, step S3 further includes providing the upper surface passivation layer between the perovskite active layer and the electron transport layer.

[0081] The method for setting the passivation layer on the upper surface includes spin-coating a PI solution onto the surface of the perovskite active layer and performing a fourth annealing. Wherein,

[0082] The concentration of the PI solution is 0.3 to 0.8 mg / mL; specifically, it can be about 0.5 mg / mL.

[0083] The solvent for the PI solution includes isopropanol.

[0084] The volume of the PI solution used is 25–45 μL / cm³. 2 For example, it could be approximately 30 μL / cm. 2 35μL / cm 2 or approximately 40 μL / cm 2 The PI solution is spin-coated at a speed of 4500–5500 rpm. For example, it can be approximately 5000 rpm.

[0085] The spin coating of the PI solution takes 25 to 35 seconds; specifically, it can be about 30 seconds.

[0086] The temperature for the fourth annealing is 90–110°C; specifically, it can be approximately 100°C.

[0087] The duration of the fourth annealing is 3 to 8 minutes; for example, it can be about 5 minutes.

[0088] According to some embodiments of the present invention, in step S3, the method for setting the electron transport layer and the metal electrode includes vacuum evaporation.

[0089] The vacuum degree required for the vacuum evaporation is approximately 4 × 10⁻⁶. -5 Torr.

[0090] The vacuum evaporation rate is For example, it could specifically be an approx.

[0091] Unless otherwise specified, spin coating mentioned in this invention can be performed using a benchtop spin coater, and annealing can be performed using a temperature-controlled heating table. However, this invention does not impose strict limitations on the equipment; in actual production, appropriate equipment can be selected for testing based on experimental requirements and conditions.

[0092] According to an embodiment of a third aspect of the present invention, an application of the perovskite solar cell is provided in terrestrial photovoltaics, space photovoltaics, or wearable devices.

[0093] Since the application adopts all the technical solutions of the perovskite solar cells in the above embodiments, it has at least all the beneficial effects brought about by the technical solutions in the above embodiments.

[0094] Unless otherwise specified, the term "about" in this invention actually means that the error is allowed to be within ±2%, for example, about 100 is actually 100 ± 2% × 100.

[0095] Unless otherwise specified, "between" in this invention includes the number itself, for example, "between 2 and 3" includes the endpoint values ​​2 and 3.

[0096] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0097] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0098] Figure 1 This is a schematic diagram of the structure of the perovskite solar cell prepared according to an embodiment of the present invention.

[0099] Figure 2 This is a KPFM diagram of the nickel oxide layer obtained in step S1 of Embodiment 1 of the present invention;

[0100] Figure 3 This is the KPFM diagram of the SAM organic modified layer obtained in step S2 of Example 1 of the present invention;

[0101] Figure 4 This is a band structure diagram of the component obtained in steps S1, S2 and S3 of Embodiment 1 of the present invention.

[0102] Figure 5 This is a band structure diagram of the component obtained in steps S2 and S3 of embodiments 1 to 3 of the present invention.

[0103] Figure 6 These are the performance statistics of the perovskite solar cells obtained in Examples 1, 4-6, Comparative Examples 1-2 and Comparative Example 4 of the present invention.

[0104] Figure 7 These are the performance statistics of the perovskite solar cells obtained in Embodiment 1, Comparative Example 1, and Comparative Examples 3-4 of the present invention.

[0105] Figure 8 These are the JV curves of the perovskite solar cells obtained in Example 1 and Comparative Example 4 of this invention.

[0106] Figure 9 These are the JV curves of the perovskite solar cells obtained in Example 2 and Comparative Example 5 of this invention.

[0107] Figure 10 These are the JV curves of the perovskite solar cells obtained in Example 3 and Comparative Example 6 of this invention. Detailed Implementation

[0108] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0109] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0110] Example 1

[0111] refer to Figure 1 Based on the structure, this example fabricates a perovskite solar cell, and the specific steps are as follows:

[0112] S1. Prepare NiO with a concentration of 10 mg / mL X The dispersion is prepared with water and IPA in a volume ratio of 4:1.

[0113] 60 μL of NiO X The dispersion was dropped onto the ITO layer side of a cleaned ITO glass (a composite structure of a transparent substrate and a transparent electrode, measuring 1.5 cm × 1.5 cm), and spin-coated at 3000 rpm for 40 s using a static spin coating method (first spin coating). The wet film was then transferred to a 110°C isothermal heating stage for annealing for 15 min (first annealing) to obtain a nickel oxide layer with a thickness of approximately 30 nm.

[0114] NiO used in this step X Purchased from Liaoning Youxuan New Energy Technology Co., Ltd., purity: 99.999%.

[0115] S2. A 1 mmol / L solution of Me-4PACz and Br-4PACz in IPA solution of the same concentration was mixed at a volume ratio of 9:1 to obtain a slurry for the second spin coating. 60 μL of the second spin coating slurry was dropped onto the surface of the nickel oxide layer, and spin-coated at 5000 rpm for 30 s using a static spin coating method (second spin coating). The wet film was then transferred to a 100°C isothermal heating stage for annealing for approximately 10 min (second annealing) to obtain a SAM organic modification layer with a thickness of approximately 1 nm, completing the preparation of the composite hole transport structure.

[0116] S3. Sequentially deposit a perovskite absorber layer, an upper surface passivation layer, an electron transport layer, and a metal electrode on the surface of the SAM organic modification layer.

[0117] S3a. Setting of the perovskite absorber layer:

[0118] According to the chemical formula Cs 0.05 FA 0.85 MA 0.1 The proportion of PbI3 (hereinafter referred to as Formula I) is used to mix MACl, CsI, MAI, FAI and PbI2 in a DMF:DMSO mixed solvent (4:1 volume ratio), and then the mixture is shaken and stirred for more than 2 hours until it becomes transparent. The resulting slurry is filtered using a 0.22 μm PTFE filter membrane to form a 1.6 mol / L perovskite precursor slurry (based on Formula I and the amount of feed).

[0119] 60 μL of perovskite precursor slurry was dropped onto the composite hole transport structure. Static spin coating was then performed at a low speed of 1000 rpm for 5 seconds, followed by a high speed of 5000 rpm for 30 seconds. Approximately 200 μL of CB antisolvent was dynamically added during the 18th–19th seconds of the high-speed spin coating. The resulting wet film was then transferred to a 100°C isothermal heating stage for annealing for approximately 30 minutes, yielding a perovskite absorber layer with a thickness of approximately 720 nm.

[0120] S3b. Setting of the passivation layer on the upper surface:

[0121] A PI solution with a concentration of 0.5 mg / mL was prepared using IPA as the solvent. 60 μL of the PI solution was spin-coated onto the perovskite absorber layer using a dynamic spin-coating method at 5000 rpm for 30 s. The wet film was then transferred to a 100°C constant-temperature heating stage for annealing for approximately 5 min to obtain the upper surface passivation layer.

[0122] S3c. Setting of electron transport layer and metal electrodes:

[0123] The component obtained in step S3b is placed on the designed evaporation mask and fixed in the vacuum evaporation apparatus chamber. Then, under a vacuum of approximately 4 × 10⁻⁶, -5 Under Torr conditions, with The evaporation rate was achieved by sequentially depositing 40 nm C through thermal evaporation. 60 8nm BCP and 100nm Cu were used to complete the fabrication of perovskite solar cells.

[0124] The effective area of ​​the perovskite solar cell obtained in this example is 0.1 cm². 2 .

[0125] Example 2

[0126] This example demonstrates the fabrication of a perovskite solar cell. The specific process differs from that in Example 1 in the following ways:

[0127] In step S2, the volume ratio of the IPA solution of Me-4PACz to Br-4PACz is 8:2;

[0128] The operation of step S3a is as follows:

[0129] According to the chemical formula Cs 0.17 FA 0.83 The proportion of PbI3 (hereinafter referred to as Formula II) is used to mix CsI, FAI, PbI2 and PbCl2 in a DMF:DMSO mixed solvent (5:1 volume ratio), and then the mixture is shaken and stirred for more than 2 hours until it becomes transparent. The resulting slurry is filtered through a 0.22 μm PTFE filter membrane to form a 2 mol / L perovskite precursor slurry (based on Formula II and the amount of feed).

[0130] 60 μL of perovskite precursor slurry was dropped onto the composite hole transport structure and spin-coated at a high speed of 5000 rpm for 40 s using a static spin coating method. The resulting wet film was then transferred to a 150°C isothermal heating stage for annealing for about 10 min to obtain the perovskite absorber layer.

[0131] Example 3

[0132] This example demonstrates the fabrication of a perovskite solar cell, which differs from Example 1 in that:

[0133] In step S2, the volume ratio of the IPA solution of Me-4PACz to Br-4PACz is 5:5;

[0134] The operation of step S3a is as follows:

[0135] According to the chemical formula Cs 0.2 Fa 0.8 PbI 1.5 Br 1.5In the proportion of (hereinafter referred to as Formula III), CsI, MAI, FAI, PbI2 and PbBr2 are mixed in a DMF:DMSO mixed solvent (3:1 volume ratio), and then shaken and stirred for more than 2 hours until transparent. The resulting slurry is filtered using a 0.22 μm PTFE filter membrane to form a 1.2 mol / L perovskite precursor slurry (based on Formula II and feed amount).

[0136] 60 μL of perovskite precursor slurry was dropped onto the composite hole transport structure. Static spin coating was performed at a low speed of 1000 rpm for 2 seconds, followed by a high speed of 3000 rpm for 40 seconds. Approximately 200 μL of CB antisolvent was dynamically added during the 28th–29th seconds of the high-speed spin coating. The resulting wet film was then transferred to a 100°C isothermal heating stage for annealing for approximately 15 minutes to obtain the perovskite thin film.

[0137] Example 4

[0138] This example demonstrates the fabrication of a perovskite solar cell, which differs from Example 1 in that:

[0139] In step S2, the volume ratio of the IPA solution of Me-4PACz to Br-4PACz is 8:2.

[0140] Example 5

[0141] This example demonstrates the fabrication of a perovskite solar cell, which differs from Example 1 in that:

[0142] In step S2, the volume ratio of the IPA solution of Me-4PACz to Br-4PACz is 5:5.

[0143] Example 6

[0144] This example demonstrates the fabrication of a perovskite solar cell, which differs from Example 1 in that:

[0145] In step S2, the volume ratio of the IPA solution of Me-4PACz to Br-4PACz is 2:8.

[0146] Comparative Example 1

[0147] This example demonstrates the fabrication of a perovskite solar cell, which differs from Example 1 in that:

[0148] The operation of step S2 is as follows:

[0149] 60 μL of a 1 mmol / L Me-4PACz IPA solution was dropped onto the surface of a nickel oxide layer, and then spin-coated at 5000 rpm for 30 s using a static spin-coating method. The wet film was then transferred to a 100°C constant-temperature heating stage for annealing for about 10 min to obtain a dry film of monomolecular SAM organic modification layer, thus completing the preparation of the composite hole transport structure.

[0150] Comparative Example 2

[0151] This example demonstrates the fabrication of a perovskite solar cell, which differs from Example 1 in that:

[0152] The operation of step S2 is as follows:

[0153] 60 μL of an IPA solution containing 1 mmol / L Br-4PACz was dropped onto the surface of a nickel oxide layer, and then spin-coated at 5000 rpm for 30 s using a static spin-coating method. The wet film was then transferred to a 100°C constant-temperature heating stage for annealing for about 10 min to obtain a dry film of monomolecular SAM organic modification layer, thus completing the preparation of the composite hole transport structure.

[0154] Comparative Example 3

[0155] This example demonstrates the fabrication of a perovskite solar cell, which differs from Example 1 in that:

[0156] The operation of step S2 is as follows:

[0157] 60 μL of a 1 mmol / L IPA solution (CAS: 20999-38-6) was dropped onto the surface of a nickel oxide layer, and then spin-coated at 5000 rpm for 30 s using a static spin-coating method. The wet film was then transferred to a 100°C constant-temperature heating stage for annealing for approximately 10 min to obtain a dry film of a monomolecular SAM organic-modified layer, thus completing the preparation of the composite hole transport structure.

[0158] Comparative Example 4

[0159] This example demonstrates the fabrication of a perovskite solar cell, which differs from Example 1 in that:

[0160] Step S2 is excluded, i.e., the perovskite active layer is directly deposited on the surface of the nickel oxide layer.

[0161] Comparative Example 5

[0162] This example demonstrates the fabrication of a perovskite solar cell, which differs from Example 2 in that:

[0163] Step S2 is excluded, i.e., the perovskite active layer is directly deposited on the surface of the nickel oxide layer.

[0164] Comparative Example 6

[0165] This example demonstrates the fabrication of a perovskite solar cell, which differs from Example 3 in that:

[0166] Step S2 is excluded, i.e., the perovskite active layer is directly deposited on the surface of the nickel oxide layer.

[0167] Test Example 1

[0168] In this example, the morphology of the nickel oxide layer obtained in step S1 and the SAM organic modification layer obtained in step S2 of Example 1 were tested using Kelvin probe force microscopy (KPFM). The results show that compared to the pure nickel oxide layer, the sample spin-coated with the SAM organic modification layer exhibits a significant negative shift in surface potential (see scale bar), indicating that the composite hole transport structure with the SAM organic modification layer exhibits a more p-type band structure, which is beneficial for interfacial hole transport. Specific results are as follows... Figures 2-3 As shown.

[0169] Test Example 2

[0170] This example calculates the band structure of the components obtained in steps S1 to S3a of Examples 1 to 3. The results show:

[0171] In Example 1, there was significant band mismatch between the nickel oxide layer and the perovskite layer. However, by adding a SAM organic modification layer with an appropriate composition ratio, the band structure of the composite hole transport structure matched the band structure of the perovskite layer, thereby significantly reducing the energy loss caused by the band mismatch. The band structure of Example 1 is as follows: Figure 4 As shown in the figure, ET-HTL-10% represents the SAM organic modification layer of Example 1, E CBM Indicates the conduction band bottom (conduction band minimum), E F Represents the Fermi level, E VBM "Evac" represents the top of the valence band, and "Evac" represents the vacuum energy level.

[0172] Examples 2 and 3, by incorporating a SAM organic modification layer, also improved the bandgap matching between the composite hole transport structure and the perovskite layer to some extent; however, as shown in the figures, the bandgap is not completely matched. In actual production, by adjusting the molar ratio of Me-4PACz to Br-4PACz in the SAM organic modification layer, a SAM organic modification layer with higher bandgap matching can be obtained for a specific perovskite active layer, thereby obtaining a perovskite solar cell with superior overall performance. A comparison of the bandgap structures in Examples 1-3 is provided. Figure 5 As shown, ET-HTL-20% represents Example 2 and ET-HTL-50% represents Example 3.

[0173] Test Example 3

[0174] The current-voltage characteristic curve (JV) is an important indicator reflecting the performance of photovoltaic cell devices. Through JV testing, the open-circuit voltage (V) of a perovskite solar cell can be obtained. OC ) and short-circuit current (J SC The fill factor (FF) of the device is calculated by combining the maximum power point (MPP), and the power conversion efficiency (PCE) of the perovskite solar cell is further obtained to measure its ability to utilize sunlight.

[0175] This example tested the current-voltage characteristics of the perovskite solar cells obtained in the embodiment and comparative examples, with an active area of ​​0.0736 cm². 2 The JV curves were obtained by forward and reverse scanning within the same bias range, with a scan rate of 0.02 V / s and a scan step size of 20 mV, under AM1.5G spectrum illumination.

[0176] Table 1. JV test parameters of the perovskite solar cells obtained in Examples 1-6 and Comparative Examples 1-6

[0177]

[0178] A comparison of the results of Examples 1-3 and Comparative Examples 4-6 shows that the present invention, by setting a composite hole transport structure containing a SAM organic modification layer in the perovskite solar cell and adjusting the ratio of Me-4PACz to Br-4PACz, can achieve good energy level matching with various perovskite active layers. Furthermore, the prepared inverted perovskite solar cell exhibits significantly improved open-circuit voltage and fill factor compared to the traditional single inorganic transport layer structure (Comparative Examples 4-6), demonstrating the effective suppression of interface losses and significant enhancement of hole extraction by the composite hole transport structure. Specifically, the PCE improvement of the corresponding examples is ≥8% compared to the comparative examples; for example, it can reach 10%, 11%, or even 12%. The test results of Examples 1-3 and Comparative Examples 4-6 are summarized in Table 1. The test results of Example 1 and Comparative Example 4 are as follows... Figure 8 As shown in the figure, NiO x Comparative Example 4 is represented by ET-HTL-10%, and Example 1 by ET-HTL-10%. The test results for Example 2 and Comparative Example 5 are as follows: Figure 9 As shown in the figure, NiO x Comparative Example 5 is represented by ET-HTL-20%, and Example 2 by ET-HTL-20%. The test results for Example 3 and Comparative Example 6 are as follows: Figure 10 As shown in the figure, NiO x Comparative Example 6 is indicated by ET-HTL-50%, which represents Example 3. Figures 8-10 In the diagram, Forward scan represents the positive scan curve, Reverse scan represents the negative scan curve, and the vertical axis represents Current density (J).SC The x-axis represents current density, and the y-axis represents Voltage (V). OC ) indicates the open-circuit voltage.

[0179] A comparison of the results of Example 1 and Comparative Examples 1-4 shows that there is a significant synergistic effect between Me-4PACz and Br-4PACz in the SAM organic modification layer, which can improve the band matching of the composite hole transport structure and the perovskite active layer, ultimately significantly improving the Vt of the obtained perovskite solar cell. OC FF, J SC And PCE; if the SAM organic modification layer contains only one self-assembled molecule, whether it is Me-4PACz, Br-4PACz, or other known self-assembled molecules, it cannot, or cannot effectively, improve the overall performance of the resulting perovskite solar cell. Specific test results are as follows: Figure 7 As shown in the figure, NiO x This refers to Comparative Example 4, NiO x / 2PACz indicates Comparative Example 3, NiO x / Me-4PACz indicates Comparative Example 1, and ET-HTL-10% indicates Example 1.

[0180] A comparison of the results of Examples 1, 4-6 and Comparative Examples 1-2, 4 shows that when the material of the perovskite active layer is constant, there is an optimal ratio of Me-4PACz to Br-4PACz in the SAM organic modification layer. For example, when the material of the perovskite active layer is Cs... 0.05 FA 0.85 MA 0.1 For PbI3, the optimal ratio of Me-4PACz:Br-4PACz is 9:1, resulting in the best overall performance of the perovskite solar cell. Deviating from this optimal ratio (Examples 4-6) will reduce the overall performance of the perovskite solar cell to some extent. Furthermore, it should be noted that the overall performance of a perovskite solar cell is primarily influenced by the choice of material for its perovskite active layer. Composite hole transport structures can only improve the performance of existing perovskite active layers to a certain extent; that is, if the materials of the perovskite active layer are different, the performance of perovskite solar cells is almost incomparable. Specific test results are as follows: Figure 6 As shown in the figure, NiO x The numbers represent Comparative Example 4, 10:0 represent Comparative Example 1, 9:1 represent Example 1, 8:2 represent Example 4, 5:5 represent Example 5, 2:8 represent Example 6, and 0:10 represent Comparative Example 2.

[0181] In summary, the interface enhancement of the composite hole transport structure is of great significance in perovskite solar cells. Suppressing interface losses and improving hole transport efficiency play a decisive role in improving the performance of perovskite solar cells. In perovskite solar cells, interface losses mainly originate from energy level mismatch and defect trapping. Therefore, this invention, through the rational design of the composite hole transport structure, achieves a more matched band structure and a lower defect level, significantly improving the hole extraction efficiency and performance of perovskite solar cells. Due to these superior characteristics, the resulting perovskite solar cell is expected to find wide applications in terrestrial photovoltaics, space photovoltaics, and wearable devices.

[0182] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A perovskite solar cell, the perovskite solar cell comprising a transparent electrode, a composite hole transport structure, a perovskite absorber layer, an electron transport layer, and a metal electrode sequentially stacked; characterized in that, The composite hole transport structure includes a nickel oxide layer and a SAM organic modification layer superimposed from the transparent electrode; The raw materials for preparing the SAM organic modification layer include a mixture of Me-4PACz and Br-4PACz in a molar ratio of 0.25 to 10:

1.

2. The perovskite solar cell according to claim 1, characterized in that, The molar ratio of Me-4PACz to Br-4PACz is 8 to 10:

1.

3. The perovskite solar cell according to claim 1, characterized in that, The material formula of the perovskite absorber layer is (Cs) x FA y MA 1-x-y )Pb(I z Br 3-z ); and / or, the material of the perovskite absorber layer includes Cs 0.05 FA 0.85 MA 0.1 PbI3, Cs 0.17 FA 0.83 PbI3 and Cs 0.2 FA 0.8 PbI 1.5 Br 1.5 At least one of them.

4. The perovskite solar cell according to any one of claims 1 to 3, characterized in that, The perovskite solar cell also includes an upper surface passivation layer disposed between the perovskite absorption layer and the electron transport layer.

5. A method for preparing a perovskite solar cell according to any one of claims 1 to 4, characterized in that, The preparation method includes the following steps: S1. The nickel oxide layer is formed on the surface of the transparent electrode; S2. The SAM organic modification layer is formed on the surface of the nickel oxide layer; S3. The perovskite absorber layer, electron transport layer and metal electrode are sequentially disposed on the surface of the SAM organic modification layer.

6. The preparation method according to claim 5, characterized in that, In step S1, the nickel oxide layer is formed by sequentially performing a first spin coating and a first annealing.

7. The preparation method according to claim 6, characterized in that, The slurry used for the first spin coating is a nickel oxide dispersion, and the solvent of the nickel oxide dispersion includes water; and / or, the temperature of the first annealing is 105-115°C.

8. The preparation method according to claim 5, characterized in that, In step S2, the SAM organic modification layer is formed by sequentially performing a second spin coating and a second annealing.

9. The preparation method according to claim 8, characterized in that, The solvent in the slurry used for the second spin coating is at least one of an alcohol solvent, DMF, and DMSO; the solute is Me-4PACz and Br-4PACz; and / or the temperature of the second annealing is 100-110°C.

10. An application of a perovskite solar cell as described in any one of claims 1 to 4 in terrestrial photovoltaics, space photovoltaics, or wearable devices.

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