Modified hole transport layer, preparation method thereof and perovskite solar cell device
By doping benzothiadiazole derivatives into self-assembled monolayers, the problems of molecular aggregation and interface defects of SAMs in perovskite solar cells were solved, and a highly efficient and stable hole transport layer was achieved, improving device performance and reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANHUA UNIV
- Filing Date
- 2026-03-24
- Publication Date
- 2026-06-16
AI Technical Summary
In the prior art, self-assembled monolayers (SAMs) in perovskite solar cells suffer from problems such as incomplete coverage due to molecular aggregation, insufficient interfacial dipole regulation, and lack of strong interaction groups with perovskite, which affect device performance and stability.
Doping self-assembled monomolecules containing phosphonic acid groups with benzothiadiazole derivatives improves coverage and uniform distribution by reducing aggregation and enhancing bond interactions, thereby promoting perovskite crystal growth, suppressing nonradiative recombination, and modulating energy levels to enhance carrier transport.
It improves the coverage and uniformity of the hole transport layer, reduces the defect density, enhances carrier transport, improves the photoelectric conversion efficiency and stability of perovskite solar cells, and reduces the dependence of the fabrication process on the environment.
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Figure CN122227772A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of perovskite solar cell technology, specifically relating to a modified hole transport layer, its preparation method, and a perovskite solar cell device. Background Technology
[0002] In recent years, inverted perovskite solar cells (PSCs) have been widely recognized as one of the main technological routes for the commercialization of third-generation photovoltaic technology due to their excellent power conversion efficiency (PCE), cost-effectiveness, and compatibility with tandem solar cells. Self-assembled monolayers (SAMs), as a novel type of hole transport layer (HTL), promote hole extraction through the interfacial dipole effect and have been widely used in high-performance inverted PSCs, with certified champion efficiencies exceeding 26%, although their efficiency is still below the Shockley-Quesel (SQ) limit. SAMs play a crucial role in inverted PSCs as a substrate supporting perovskite nucleation and crystallization, and as a means of promoting carrier transport. Their properties are mainly determined by several factors, including molecular structure and adsorption mode. Traditionally, SAM-based hole transport layers (HTLs) are typically achieved through a self-assembly process where anchoring groups such as thiols (-SH), phosphonic acids (-PO3H2), or carboxyl groups (-COOH) interact with hydroxyl groups on the substrate surface, forming an organic monolayer on the substrate. However, in actual deposition processes, the intrinsic amphiphilicity of most SAM molecules tends to promote aggregation, which leads to poor repeatability of inverted PSCs and insufficient charge extraction at the buried layer interface, thus affecting device performance.
[0003] Therefore, simple SAMs systems not only face the problem of incomplete coverage due to molecular aggregation, but also suffer from insufficient interfacial dipole modulation and a lack of strong interacting groups with the perovskite. This leads to a decrease in the crystallinity of the perovskite and an increase in nonradiative recombination of charge carriers at the buried layer interface, directly affecting device performance and long-term stability.
[0004] Existing technology (Tan Q, Li Z, Luo G, et al. Inverted perovskite solar cells using dimethylacridine-based dopants[J]. Scientific Reports, 2022, 12(1):11.DOI:10.1038 / s41586-023-06207-0.) employs a co-adsorption strategy, introducing auxiliary molecules (such as PyCA-3F) into the host SAM molecule (such as 2PACz), forming a co-adsorption layer through intermolecular interactions (hydrogen bonds, electrostatic interactions). The PyCA-3F molecule has a structure containing a carboxyl group (-COOH) anchoring group and a trifluoromethyl group (-CF3). Through hydrogen bonding, it inhibits the aggregation of the host molecule, and the auxiliary molecule fills the gaps in the host SAM, improving the coverage; at the same time, it adjusts the work function and optimizes the energy level alignment. The host and auxiliary molecules are mixed in proportion and dissolved in a solvent, spin-coated onto the substrate, and then annealed at low temperature. However, molecular screening requires complex auxiliary molecules containing hydrophilic groups (such as -NH2, -COOH) and sterically hindered groups, resulting in high design and synthesis costs. Furthermore, deviations in the mixing ratio can easily lead to competitive adsorption of molecules, reducing coverage uniformity.
[0005] Existing technology 2 (Jiang W, Qu G, Huang X, et al. Toughened self-assembled monolayers for durable perovskite solar cells[J]. Nature, 2010, 646(8083):16.DOI:10.1038 / s41586-025-09509-7.) employs an in-situ crosslinking strategy, introducing a crosslinking agent containing reactive groups (such as the azide molecule JJ24) into the host SAM (such as CbzNaph), triggering covalent crosslinking through heat treatment. The JJ24 molecule acts as an azide group (-N3) that crosslinks with the CbzNaph alkyl chain at 150℃, forming a rigid network structure. The mechanism of action is that crosslinking inhibits molecular wobble, reducing substrate exposure; at the same time, it enhances the nucleation guidance of perovskite and reduces interfacial non-radiative recombination. After bimolecular co-deposition, annealing at 150℃ for 10 minutes activates the crosslinking reaction. However, it is dependent on high temperatures, requiring annealing above 150°C for crosslinking, and flexible substrates (such as polyimide) are prone to deformation. There is also a risk of side reactions; azide groups may decompose and generate gas at high temperatures, leading to interfacial porosity (requiring an inert atmosphere for protection). The crosslinking agent needs to match the chain length of the host molecular chain (e.g., the carbon chain length of JJ24 needs to be adapted to CbzNaph), resulting in low design flexibility.
[0006] Existing technology 3 (Fu J, Zhang J, Zhang T, et al. Synergistic Effects of Interfacial Energy Level Regulation and Stress Relaxation via a Buried Interface for Highly Efficient Perovskite Solar Cells[J]. ACS nano, 2023.DOI:10.1021 / acsnano.2c11091.) employs an amphiphilic molecule strategy to design amphiphilic molecules (such as MPA-CPA) containing hydrophilic head groups and hydrophobic tail groups, forming a bilayer structure with the host SAM to improve wettability. The MPA-CPA structure uses a thiol (-SH) group to anchor the substrate, while the carboxyl group (-COOH) faces upward to enhance hydrophilicity. The hydrophobic chain isolates polar solvents, and the hydrophilic head group improves the spreadability of the perovskite precursor solution and reduces pinholes. After the host SAM is deposited, the amphiphilic molecule solution is spin-coated to self-assemble into a bilayer. However, the amphiphilic molecule requires precise control of the hydrophilic-hydrophobic balance (HLB value), resulting in low synthesis yields. Increased thickness of the bilayer structure may introduce additional series resistance. Some amphiphilic molecules (such as those containing quaternary ammonium salts) readily react with perovskite components, generating insulating impurities.
[0007] In summary, the main SAM molecules modified by the above organic materials exhibit poor interfacial stability and numerous defects at the interface with the perovskite active layer. Summary of the Invention
[0008] The purpose of this invention is to provide a modified hole transport layer, its preparation method, and a perovskite solar cell device. By doping phosphonic acid-containing SAM molecules with benzothiadiazole derivatives, the aggregation of 4PADCB is reduced, and the bond interactions of 4PADCB are enhanced, thereby improving the coverage and uniform distribution of SAM, thus achieving a highly efficient and stable inverted perovskite solar cell.
[0009] The present invention solves the above-mentioned technical problems through the following technical solutions.
[0010] The first objective of this invention is to provide a modified hole transport layer, comprising a hole transport layer and a benzothiadiazole derivative doped in the hole transport layer. The hole transport layer is made of a self-assembled monomolecule containing phosphonic acid groups, and the structural formula of the benzothiadiazole derivative is as follows: ; Where R is H, F, Cl or Br.
[0011] Furthermore, the benzothiadiazole derivatives are 5-fluorobenzene-[2,1,3]-thiadiazonium, 5-fluorobenzene-[2,1,3]-thiadiazonium, or 2,1,3-benzothiadiazole.
[0012] Furthermore, the self-assembled monomers containing phosphonic acid groups are 4-(7H-dibenzo[c,g]carbazole-7-yl)butylphosphonic acid or (2-(9H-carbazole-9-yl)ethyl)phosphonic acid.
[0013] A second objective of this invention is to provide a method for preparing the modified hole transport layer described above, comprising the following steps: A benzothiadiazole derivative was added to a self-assembled molecular dispersion containing phosphonic acid groups, mixed thoroughly, coated onto a substrate, and annealed to obtain a modified hole transport layer.
[0014] Furthermore, the doping amount of the benzothiadiazole derivative is 0.1 wt.% to 10 wt.%.
[0015] Furthermore, the annealing temperature is ~120℃, and the time is 8 min to 12 min.
[0016] The third objective of this invention is to provide a perovskite solar cell device, wherein the perovskite solar cell device comprises, from bottom to top along the thickness direction, a substrate, a cathode layer, a hole transport layer, a perovskite polycrystalline thin film layer, an electron transport layer, and an anode layer, wherein the hole transport layer is the aforementioned modified hole transport layer.
[0017] Furthermore, the cathode layer is made of gold, copper, silver, zinc, indium tin oxide, zinc oxide, tin oxide, polythiophene, sodium benzenesulfonate of polyethylene, or polyaniline; the electron transport layer is made of tin oxide, titanium oxide, zinc oxide, fullerene, or fullerene derivatives; and the anode layer is made of gold, silver, copper, or aluminum.
[0018] Furthermore, the perovskite polycrystalline thin film layer is made of ABX3 type perovskite.
[0019] Furthermore, the thickness of the cathode layer is 80nm–120nm, the thickness of the hole transport layer is 30nm–60nm, the thickness of the perovskite polycrystalline thin film layer is 300nm–400nm, the thickness of the electron transport layer is 30nm–40nm, and the thickness of the anode layer is 90nm–100nm.
[0020] Compared with the prior art, the present invention has the following advantages: This invention modifies the hole transport layer by doping self-assembled monomolecules containing phosphonic acid groups with specific benzothiadiazole derivatives. On one hand, this reduces the aggregation of phosphonic acid-containing SAM molecules and enhances their bond interactions, improving SAM coverage and uniform distribution. On the other hand, the doping with benzothiadiazole derivatives does not affect the crystal structure of 4PADCB, thus not only avoiding an increase in lattice distortion defects but also reducing the defect density in SAM molecules through the coordination effect of halogens and phosphate groups in the halide. Furthermore, the benzothiadiazole derivatives not only promote the growth of larger perovskite crystals and reduce nano-gap, but also demonstrate that mixed SAMs can suppress nonradiative recombination, accelerate carrier transport, and regulate the energy levels of SAMs; effectively improving the performance of the transport layer material and passivating defects at the interface between the transport layer and the perovskite active layer, thereby effectively improving the photoelectric conversion efficiency of perovskite solar cells.
[0021] This invention utilizes commercially available SAM molecular solutions for simple doping with benzothiadiazole derivatives. The process is simple, low-cost, and capable of large-scale preparation. Simultaneously, the benzothiadiazole derivatives exhibit excellent stability, effectively reducing the impact of the solvent in the upper perovskite precursor solution and the high temperatures during preparation. It boasts high reproducibility and low environmental dependence. Doping with benzothiadiazole derivatives does not affect the crystal structure of SAM molecules; therefore, it not only avoids increasing lattice distortion defects but also reduces the defect density in SAM molecules through the coordination effect of halogens and phosphate groups in the halide. This solves the problems of high cost and complex processes in the modification of existing SAM molecular transport materials, while enabling modified SAM molecular transport layer materials to possess both high conductivity and low defect state density, thus facilitating the large-scale application of perovskite devices. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of a perovskite solar cell device.
[0023] Figure 2 This is a comparison graph of the voltage-current density curves of the perovskite solar cell devices of Examples 1 to 3 and Comparative Example 1 of the present invention.
[0024] Figure 3 This is a graph showing the photoelectric conversion efficiency of the perovskite solar cell device in Example 1 of the present invention. Detailed Implementation
[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0026] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.
[0027] On one hand, the present invention provides a modified hole transport layer, the modified hole transport layer comprising a hole transport layer and a benzothiadiazole derivative doped in the hole transport layer, wherein the hole transport layer is a self-assembled monomolecule containing phosphonic acid groups, and the structural formula of the benzothiadiazole derivative is: ; Where R is H, F, Cl or Br.
[0028] In this invention, the self-assembled single molecules containing phosphonic acid groups are commercially prepared SAM molecules. By doping with benzothiadiazole derivatives, the hole transport layer is modified. On one hand, this reduces the aggregation of phosphonic acid-containing SAM molecules and enhances their bond interactions, thereby improving SAM coverage and uniform distribution. On the other hand, the doping with benzothiadiazole derivatives does not affect the crystal structure of 4PADCB, thus not only avoiding an increase in lattice distortion defects but also reducing the defect density in SAM molecules through the coordination effect of halogens and phosphate groups in the halide. Furthermore, the benzothiadiazole derivatives not only promote the growth of larger perovskite crystals and reduce nano-gap, but also further demonstrate that mixed SAMs can suppress nonradiative recombination, accelerate carrier transport, and regulate the energy levels of SAMs; effectively improving the performance of the transport layer material and effectively passivating defects at the interface between the transport layer and the perovskite active layer, thereby effectively improving the photoelectric conversion efficiency of perovskite solar cells.
[0029] The doped benzothiadiazole derivatives are not limited to the one or more structures mentioned above. The combination of benzothiadiazole with different halogens determines that benzothiadiazole derivatives are a universal defect passivation material.
[0030] In this invention, the benzothiadiazole derivative is 5-fluorobenzyl-[2,1,3]thiadiazol, 5,6-difluorobenzo[1,2,5]thiadiazole, or 2,1,3-benzothiadiazole. As a preferred embodiment of this invention, the benzothiadiazole derivative is 5-fluorobenzyl-[2,1,3]thiadiazol, which improves the transport performance and wettability of the hole transport layer, while reducing defects at the interface between the bottom transport layer and the photoactive layer. This leads to reduced carrier extraction, defect state density, and interface defects in the hole transport layer material, resulting in stable performance improvements from the inside of the transport layer to the transport layer interface. This enhances the efficiency of perovskite solar cell devices and facilitates further applications of perovskite solar cells.
[0031] In this invention, the self-assembled monomolecule containing phosphonic acid groups is 4-(7H-dibenzo[c,g]carbazole-7-yl)butylphosphonic acid or (2-(9H-carbazole-9-yl)ethyl)phosphonic acid. As a preferred embodiment, the self-assembled monomolecule containing phosphonic acid groups is 4-(7H-dibenzo[c,g]carbazole-7-yl)butylphosphonic acid (4PADCB). Commercially prepared 4PADCB is selected, and through simple doping treatment, the performance of the 4PADCB transport material can be significantly modified, improving the photoelectric conversion efficiency of the perovskite solar cell to 26.3%, maintaining an initial efficiency of 94.6% after 1000 hours.
[0032] A second objective of this invention is to provide a method for preparing the modified hole transport layer described above, comprising the following steps: A benzothiadiazole derivative was added to a self-assembled monomolecular dispersion containing phosphonic acid groups, wherein the doping amount of the benzothiadiazole derivative was 0.1 wt.% to 10 wt.%. After being mixed evenly, the mixture was coated onto a substrate and annealed at 100°C for 10 min to obtain a modified hole transport layer.
[0033] This invention utilizes commercially available SAM molecular solutions for simple doping with benzothiadiazole derivatives. The process is simple, low-cost, and capable of large-scale preparation. Simultaneously, the benzothiadiazole derivatives exhibit excellent stability, effectively reducing the impact of the solvent in the upper perovskite precursor solution and the high temperatures during preparation. It boasts high reproducibility and low environmental dependence. Doping with benzothiadiazole derivatives does not affect the crystal structure of SAM molecules; therefore, it not only avoids increasing lattice distortion defects but also reduces the defect density in SAM molecules through the coordination effect of halogens and phosphate groups in the halide. This solves the problems of high cost, complex processes, and poor stability in existing SAM molecular transport materials, while enabling modified SAM molecular transport layer materials to possess both high conductivity and low defect state density, thus facilitating the large-scale application of perovskite devices.
[0034] In this invention, by adjusting the concentration of benzothiadiazole derivatives, various types of underlying transport layer materials and perovskite light-absorbing layers can be modified.
[0035] A third objective of this invention is to provide a perovskite solar cell device, such as... Figure 1 As shown, the perovskite solar cell device includes, from bottom to top along the thickness direction, a substrate 1, a cathode layer 2, a hole transport layer 3, a perovskite polycrystalline thin film layer 4, an electron transport layer 5, and an anode layer 6, wherein the hole transport layer 3 is the modified hole transport layer described above.
[0036] In this invention, the substrate is made of glass or a flexible substrate, wherein the flexible substrate is a polyester or polyimide compound.
[0037] In this invention, the cathode layer is made of metal, metal oxide, or organic conductive polymer. The metal is gold, copper, silver, or zinc; the metal oxide is indium tin oxide, zinc oxide, or tin oxide; and the organic conductive polymer is polythiophene, sodium poly(benzenesulfonate), or polyaniline.
[0038] In this invention, the electron transport layer is made of tin oxide, titanium oxide, zinc oxide, fullerene, or a fullerene derivative.
[0039] In this invention, the anode layer is made of gold, silver, copper or aluminum.
[0040] In this invention, the perovskite polycrystalline thin film layer is made of ABX3 type perovskite. ABX3 type perovskite can be modified using existing conventional techniques and is not limited to one or more structures. This invention significantly improves the stability of both organic and inorganic perovskite materials of the universally applicable ABX3 type perovskite.
[0041] Furthermore, the thickness of the cathode layer is 80nm to 120nm, the thickness of the hole transport layer is 30nm to 60nm, the thickness of the perovskite polycrystalline thin film layer is 300nm to 400nm, the thickness of the electron transport layer is 30nm to 40nm, and the thickness of the anode layer is 90nm to 100nm.
[0042] The following specific examples provide further details. In these examples, 5-fluorobenzyl-[2,1,3]thiadiazo is abbreviated as FBT, 5,6-difluorobenzo[1,2,5]thiadiazole is abbreviated as DFBT, 2,1,3-benzothiadiazole is abbreviated as BT, and 4-(7H-dibenzo[c,g]carbazole-7-yl)butylphosphonic acid is abbreviated as 4PADCB.
[0043] Example 1 A perovskite solar cell device, such as Figure 1As shown, the perovskite solar cell device has the following structure: glass (plastic) substrate 1 / ITO (cathode layer 2) / modified hole transport layer 3 / perovskite layer 4 / electron transport layer 5 / anode layer 6; the modified hole transport layer 3 is doped with 5-fluorobenzene-[2,1,3]-thiadiazo.
[0044] The fabrication method of the above-mentioned perovskite solar cell device includes the following steps: S1. The transparent conductive substrate 1 (with an ITO glass layer on it) is cleaned by ultrasonication with ethanol, ITO cleaning solution and deionized water. After cleaning, it is dried under an infrared lamp. The ITO film on the transparent substrate 1 serves as the cathode layer 2 of the device. The sheet resistance of the ITO film is 15Ω and the film thickness is 100nm.
[0045] S2, Modified Hole Transport Layer 3: The cathode layer 2 was treated with UV-ozone for 10 minutes. 4PADCB nanoparticles were dispersed in isopropanol to form a dispersion. Then, FBT was added at a concentration of 2 mg / mL to obtain a precursor solution. The precursor solution was spin-coated onto the cathode layer 2 at 5000 rpm for 30 seconds using a spin coater. The mixture was then annealed at 100°C for 10 minutes to obtain a modified hole transport layer with a thickness of 30 nm.
[0046] S3, Perovskite Layer 4: Perovskite thin film layer 4 was prepared using an anti-solvent one-step spin-coating method. 866 mg of PbI2, 261 mg of FAI, 21 mg of CSI, and 22 mg of MACL were weighed and added sequentially to a mixed solution of 0.8 mL of DMF and 0.2 mL of DMSO to form a precursor solution, which was stirred overnight. After filtration, the solution was spin-coated onto the modified hole transport layer 3 at 5000 rpm for 45 s, with 0.15 mL of chlorobenzene added dropwise during the final 10 s of spin-coating. After spin-coating, the film was annealed at 120 °C for 15 min to obtain perovskite layer 4, which has a thickness of 300 nm.
[0047] S4, Electron transport layer 5: Under vacuum conditions, C60 is deposited on the perovskite layer 4 at a deposition rate of 0.04 nm / s to obtain electron transport layer 5, which has a thickness of 40 nm.
[0048] Preparation of S5 and anode layer 6: Under vacuum conditions, metallic copper is deposited on electron transport layer 5 at a deposition rate of 0.1 nm / s to obtain anode layer 6 with a thickness of 100 nm. This yields the perovskite solar cell device.
[0049] Example 2 A perovskite solar cell device, such as Figure 1As shown, the perovskite solar cell device has the following structure: glass (plastic) substrate 1 / ITO (cathode layer 2) / modified hole transport layer 3 / perovskite layer 4 / electron transport layer 5 / anode layer 6; the modified hole transport layer 3 is doped with 5,6-difluorobenzo[1,2,5]thiadiazole.
[0050] The fabrication method of the above-mentioned perovskite solar cell device includes the following steps: S1. The transparent conductive substrate 1 (with an ITO glass layer on it) is cleaned by ultrasonication with ethanol, ITO cleaning solution and deionized water. After cleaning, it is dried under an infrared lamp. The ITO film on the transparent substrate 1 serves as the cathode layer 2 of the device. The sheet resistance of the ITO film is 15Ω and the film thickness is 100nm.
[0051] S2, Modified Hole Transport Layer 3: The cathode layer 2 was treated with UV-ozone for 10 minutes. 4PADCB nanoparticles were dispersed in isopropanol to form a dispersion. Then, DFBT was added at a concentration of 2 mg / mL to obtain a precursor solution. The precursor solution was spin-coated onto the cathode layer 2 at 5000 rpm for 30 seconds using a spin coater. The solution was then annealed at 100°C for 10 minutes to obtain a modified hole transport layer with a thickness of 30 nm.
[0052] S3, Perovskite Layer 4: Perovskite thin film layer 4 was prepared using an anti-solvent one-step spin-coating method. 866 mg of PbI2, 261 mg of FAI, 21 mg of CSI, and 22 mg of MACL were weighed and added sequentially to a mixed solution of 0.8 mL of DMF and 0.2 mL of DMSO to form a precursor solution, which was stirred overnight. After filtration, the solution was spin-coated onto the modified hole transport layer 3 at 5000 rpm for 45 s, with 0.15 mL of chlorobenzene added dropwise during the final 10 s of spin-coating. After spin-coating, the film was annealed at 120 °C for 15 min to obtain perovskite layer 4, which has a thickness of 300 nm.
[0053] S4, Electron transport layer 5: Under vacuum conditions, C60 is deposited on the perovskite layer 4 at a deposition rate of 0.03 nm / s to 0.04 nm / s to obtain electron transport layer 5, which has a thickness of 40 nm.
[0054] Preparation of S5 and anode layer 6: Under vacuum conditions, metallic copper is deposited on electron transport layer 5 at a deposition rate of 0.1 nm / s to obtain anode layer 6 with a thickness of 100 nm. This yields the perovskite solar cell device.
[0055] Example 3 A perovskite solar cell device, such as Figure 1As shown, the perovskite solar cell device has the following structure: glass (plastic) substrate 1 / ITO (cathode layer 2) / modified hole transport layer 3 / perovskite layer 4 / electron transport layer 5 / anode layer 6; the modified hole transport layer 3 is doped with 2,1,3-benzothiadiazole.
[0056] The fabrication method of the above-mentioned perovskite solar cell device includes the following steps: S1. The transparent conductive substrate 1 (with an ITO glass layer on it) is cleaned by ultrasonication with ethanol, ITO cleaning solution and deionized water. After cleaning, it is dried under an infrared lamp. The ITO film on the transparent substrate 1 serves as the cathode layer 2 of the device. The sheet resistance of the ITO film is 15Ω to 30Ω and the film thickness is 80 to 120nm.
[0057] S2, Modified Hole Transport Layer 3: The cathode layer 2 was treated with UV-ozone for 10 minutes. 4PADCB nanoparticles were dispersed in isopropanol to form a dispersion. Then, BT was added at a concentration of 2 mg / mL to obtain a precursor solution. The precursor solution was spin-coated onto the cathode layer 2 at 5000 rpm for 30 seconds using a spin coater. The mixture was then annealed at 100°C for 10 minutes to obtain a modified hole transport layer with a thickness of 30 nm.
[0058] S3, Perovskite Layer 4: Perovskite thin film layer 4 was prepared using an anti-solvent one-step spin-coating method. 866 mg of PbI2, 261 mg of FAI, 21 mg of CSI, and 22 mg of MACL were weighed and added sequentially to a mixed solution of 0.8 mL of DMF and 0.2 mL of DMSO to form a precursor solution, which was stirred overnight. After filtration, the solution was spin-coated onto the modified hole transport layer 3 at 5000 rpm for 45 s, with 0.15 mL of chlorobenzene added dropwise during the final 10 s of spin-coating. After spin-coating, the film was annealed at 120 °C for 15 min to obtain perovskite layer 4, which has a thickness of 300 nm.
[0059] S4, Electron transport layer 5: Under vacuum conditions, C60 is deposited on the perovskite layer 4 at a deposition rate of 0.03 nm / s to 0.04 nm / s to obtain electron transport layer 5, which has a thickness of 40 nm.
[0060] Preparation of S5 and anode layer 6: Under vacuum conditions, metallic copper is deposited on electron transport layer 5 at a deposition rate of 0.1 nm / s to obtain anode layer 6 with a thickness of 100 nm. This yields the perovskite solar cell device.
[0061] Comparative Example 1 A perovskite solar cell device, such as Figure 1As shown, the perovskite solar cell device has the following structure: glass (plastic) substrate 1 / ITO (cathode layer 2) / hole transport layer 3 / perovskite layer 4 / electron transport layer 5 / anode layer 6.
[0062] The fabrication method of the above-mentioned perovskite solar cell device includes the following steps: S1. The transparent conductive substrate 1 (ITO glass) is cleaned by ultrasonication with ethanol, ITO cleaning solution and deionized water. After cleaning, it is dried under an infrared lamp. The ITO film on the transparent substrate 1 serves as the cathode layer 2 of the device. The sheet resistance of the ITO film is 15Ω to 30Ω and the film thickness is 80 to 120nm.
[0063] S2, Hole transport layer 3: The cathode layer 2 is treated with ultraviolet-ozone for 5-10 minutes, and 4PADCB nanoparticles are dispersed in isopropanol to form a dispersion, thus obtaining a precursor solution. The precursor solution is spin-coated onto the cathode layer 2 at 5000 rpm for 30 seconds using a spin coater, and then annealed at 100°C for 10 minutes to obtain the hole transport layer 3, which has a thickness of 30 nm.
[0064] S3, Perovskite Layer 4: Perovskite thin film layer 4 was prepared using an anti-solvent one-step spin-coating method. 866 mg of PbI2, 261 mg of FAI, 21 mg of CSI, and 22 mg of MACL were weighed and added sequentially to a mixed solution of 0.8 mL of DMF and 0.2 mL of DMSO to form a precursor solution, which was stirred overnight. After filtration, the solution was spin-coated onto the modified hole transport layer 3 at 5000 rpm for 45 s, with 0.15 mL of chlorobenzene added dropwise during the final 10 s of spin-coating. After spin-coating, the film was annealed at 120 °C for 15 min to obtain perovskite layer 4, which has a thickness of 300 nm.
[0065] S4, Electron transport layer 5: Under vacuum conditions, C60 is deposited on the perovskite layer 4 at a deposition rate of 0.03 nm / s to 0.04 nm / s to obtain electron transport layer 5, which has a thickness of 40 nm.
[0066] Preparation of S5 and anode layer 6: Under vacuum conditions, metallic copper is deposited on electron transport layer 5 at a deposition rate of 0.1 nm / s to obtain anode layer 6 with a thickness of 100 nm. This yields the perovskite solar cell device.
[0067] Figure 2 This is a comparison chart of the voltage-current density curves of the perovskite solar cell devices of Examples 1 to 3 and Comparative Example 1 of the present invention. Figure 3Compared to Comparative Example 1 without benzothiadiazole derivative, the devices fabricated from the perovskite layers treated with benzothiadiazole derivative in Examples 1-3 showed a significant improvement in device performance. In Example 1, the short-circuit current increased from 25.6 mA to 26.2 mA, and the energy conversion efficiency increased from 24.8% to 26.1%; in Example 2, the short-circuit current increased from 25.6 mA to 26.0 mA, and the energy conversion efficiency increased from 24.8% to 25.6%; in Example 3, the short-circuit current increased from 25.6 mA to 25.9 mA, and the energy conversion efficiency increased from 24.8% to 25.4%.
[0068] Figure 3 This is a graph showing the photoelectric conversion efficiency of the perovskite solar cell device in Embodiment 1 of the present invention. Figure 3 As shown, commercially prepared 4PADCB was selected, and its performance as a transport material was significantly modified by simple doping treatment, thereby improving the photoelectric conversion efficiency of perovskite solar cells. The photoelectric conversion efficiency was increased to 26.3%, and the initial efficiency of 94.6% was maintained after 1000h.
[0069] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.
[0070] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A modified hole transport layer, characterized in that, The modified hole transport layer comprises a hole transport layer and a benzothiadiazole derivative doped in the hole transport layer. The hole transport layer is a self-assembled monomolecule containing phosphonic acid groups, and the structural formula of the benzothiadiazole derivative is as follows: ； Where R is H, F, Cl or Br.
2. The modified hole transport layer according to claim 1, characterized in that, The benzothiadiazole derivatives are 5-fluorobenzene-[2,1,3]-thiadiazo, 5-fluorobenzene-[2,1,3]-thiadiazo, or 2,1,3-benzothiadiazole.
3. The modified hole transport layer according to claim 1, characterized in that, The self-assembled monomers containing phosphonic acid groups are 4-(7H-dibenzo[c,g]carbazole-7-yl)butylphosphonic acid or (2-(9H-carbazole-9-yl)ethyl)phosphonic acid.
4. A method for preparing a modified hole transport layer according to any one of claims 1 to 3, characterized in that, Includes the following steps: A benzothiadiazole derivative was added to a self-assembled molecular dispersion containing phosphonic acid groups, mixed thoroughly, coated onto a substrate, and annealed to obtain a modified hole transport layer.
5. The method for preparing the modified hole transport layer according to claim 4, characterized in that, The doping amount of benzothiadiazole derivatives is 0.1 wt.% to 10 wt.%.
6. The method for preparing the modified hole transport layer according to claim 4, characterized in that, The annealing temperature is 100℃~120℃, and the time is 8min~12min.
7. A perovskite solar cell device, characterized in that, The perovskite solar cell device comprises, from bottom to top along the thickness direction, a substrate, a cathode layer, a hole transport layer, a perovskite polycrystalline thin film layer, an electron transport layer, and an anode layer, wherein the hole transport layer is the modified hole transport layer as described in any one of claims 1 to 3.
8. The perovskite solar cell device according to claim 7, characterized in that, The cathode layer is made of gold, copper, silver, zinc, indium tin oxide, zinc oxide, tin oxide, polythiophene, sodium benzenesulfonate of polyethylene, or polyaniline; the electron transport layer is made of tin oxide, titanium oxide, zinc oxide, fullerene, or fullerene derivatives; and the anode layer is made of gold, silver, copper, or aluminum.
9. The perovskite solar cell device according to claim 7, characterized in that, The material of the perovskite polycrystalline thin film layer is ABX3 type perovskite.
10. The perovskite solar cell device according to claim 7, characterized in that, The thickness of the cathode layer is 80nm–120nm, the thickness of the hole transport layer is 30nm–60nm, the thickness of the perovskite polycrystalline thin film layer is 300nm–400nm, the thickness of the electron transport layer is 30nm–40nm, and the thickness of the anode layer is 90nm–100nm.