Tin-containing perovskite solar cell with phenol derivative doped hole transport layer and preparation method thereof

Abstract

The invention discloses a tin-containing perovskite solar cell with a phenolic derivative doped hole transport layer and a preparation method of the tin-containing perovskite solar cell, and belongs to the technical field of solar cells. The device structure of the perovskite solar cell sequentially comprises a transparent conductive oxide substrate, a phenolic derivative doped hole transport layer, a perovskite active layer, an electron transport layer and a metal electrode from bottom to top. The hole transport layer is a PEDOT: PSS layer, the phenol derivative has a C6-Cx carbon chain structure, C6 is a benzene ring, Cx is a carbon-containing benzene ring substituent, and 1-3 hydroxyls are connected to the benzene ring. Phenolic derivatives are adopted to dope PEDOT: PSS, the photoelectric property of the hole transport layer is improved, reductive phenolic hydroxyl groups can passivate defects of a buried interface of the perovskite layer, Sn < 2 + > oxidation at the interface can be inhibited, the growth process of the perovskite layer thin film is optimized, non-radiative recombination of carriers is reduced, and the photoelectric performance of the hole transport layer is improved. The efficiency and the stability of the tin-containing perovskite solar cell prepared on the basis of the phenolic derivative passivated perovskite layer buried interface are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and particularly relates to a tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer and a preparation method thereof. Background Art

[0002] Organic-inorganic hybrid perovskite solar cells (PSCs) have received extensive attention due to their excellent optoelectronic properties and have shown great promise in the photovoltaic field. However, the toxicity of lead in lead-based perovskites is one of the most controversial issues in the industrialization development of PSCs, which will cause harm to human health and the natural environment when exposed to the environment. In addition, the band gaps of lead-based perovskite materials in current high-efficiency PSCs are mostly in the range of 1.5 - 1.6 eV. According to the S-Q limit efficiency theory, the certified efficiency of lead-based PSCs has approached the best efficiency that can be achieved. To overcome the above problems of lead-based perovskites, researchers have tried to study new lead-free perovskite solar cells.

[0003] Among them, tin-containing perovskites have become ideal candidate materials for lead-based perovskites due to their low toxicity, excellent optoelectronic properties, and ideal narrow band gap characteristics (1.2 - 1.4 eV). However, due to severe oxidation of the tin-containing perovskite film Sn 2+ and problems of heterogeneous nucleation and rapid crystallization, the quality of the prepared perovskite film is poor, and the density of interfacial defect states is high, which severely limits the performance improvement of tin-containing PSCs. Researchers have developed various optimization strategies such as composition regulation, additive engineering, and interface modification to overcome the inherent defects of tin-containing perovskites. In addition, developing and optimizing charge transport materials and adjusting their surface characteristics are also effective methods for preparing high-performance tin-containing PSCs.

[0004] In p-i-n structured PSCs, the bottom HTLs have a direct impact on charge extraction and transport, the nature of the buried interface, and the growth process of perovskites. Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) has excellent optoelectronic properties and high hole extraction ability and is widely used as the HTLs for tin-containing PSCs. However, the hygroscopicity and acidity of PEDOT:PSS will accelerate the degradation of tin-containing perovskites at the buried interface, affecting the long-term stability of the device. The low conductivity of the PEDOT:PSS film also results in low charge transport efficiency within the layer. By doping PEDOT:PSS and optimizing the buried interface, the device performance of tin-containing PSCs can be further improved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer and a preparation method thereof, aiming at the inherent defects of the hole transport layer PEDOT:PSS widely used in tin-containing perovskite solar cells, such as low conductivity, hygroscopicity and acidity, which lead to low efficiency and stability of perovskite solar cells. By doping phenolic derivatives in PEDOT:PSS, the electrical properties of the hole transport layer are improved, and the charge transport efficiency of the device is enhanced. In addition, phenolic derivatives have phenolic hydroxyl groups with reducibility, which can inhibit the Sn 2+ oxidation at the buried bottom interface of the tin-containing perovskite film, reduce the high defect density at the buried bottom interface and inhibit the non-radiative recombination loss at the interface, thereby significantly improving the efficiency and stability of the tin-containing perovskite solar cell.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer. The device structure of the perovskite solar cell is, from bottom to top in sequence, a transparent conductive oxide substrate, a phenolic derivative-doped hole transport layer, a perovskite active layer, an electron transport layer and a metal electrode. The phenolic derivatives include, but are not limited to, one or more of phenolic hydroxyl group-containing compounds such as simple phenolic acids like hydroxybenzoic acids, cinnamic acids, methoxyphenols, flavonoids, tannins, anthocyanins, lignans, etc.

[0008] Preferably, the hole transport layer can be at least one of various types of PEDOT:PSS such as PEDOT:PSS 4083, PEDOT:PSS PH1000, etc.

[0009] Preferably, the perovskite active layer is all organic-inorganic hybrid perovskites or all-inorganic perovskite materials containing metal tin cations, with the structural formula ABX3, including but not limited to CsSn x Pb 1-x I3 (0 < x ≤ 1), FA x MA 1-x Sn y Pb 1-y I3 (0 ≤ x ≤ 1, 0 < y ≤ 1), Cs x FA y MA 1-x-y Sn z Pb 1-z I3 (0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 < z ≤ 1), etc.

[0010] Preferably, the solvent of the perovskite active layer can be, but is not limited to, one or more of various organic solvents such as N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone (GBL), γ-valerolactone (GVL), N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAC), N,N-dimethylpropyleneurea (DMPU), acetonitrile, 2-mercaptoethanol (ME), 1,3-dimethyl-2-imidazolidinone (DMI), etc., or ionic liquids such as methylammonium formate, methylammonium acetate, methylammonium propionate, methylammonium butyrate, dimethylammonium acetate. Taking the dissolution in DMF and DMSO as an example, the volume ratio range of DMF and DMSO solvents can be, but is not limited to, 1:19 - 19:1, and the preferred range is 19:1 - 1:1.

[0011] Preferably, the substrate of the tin-containing perovskite solar cell can be, but is not limited to, at least one of flexible or rigid substrates such as glass coated with a transparent conductive oxide film, silicon wafer, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), etc. The transparent conductive oxide film can be, but is not limited to, at least one of oxide thin films such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), indium-doped zinc oxide (IZO), fluorine-doped tin oxide (FTO), indium tungsten oxide (IWO), indium cerium oxide (ICO), etc.

[0012] Preferably, the electron transport layer can be, but is not limited to, fullerenes and their derivatives, such as C 60 60, PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), ICBA (indole-C60 bisadduct), etc., or non-fullerene materials, such as at least one of n-type conjugated polymer materials, n-type organic small molecules, and n-type metal oxides.

[0013] Preferably, the metal electrode can be, but is not limited to, at least one of various metal electrodes such as Au, Ag, Cu, Bi, etc.

[0014] The present invention also provides a preparation method of a tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer, comprising the following steps:

[0015] In the steps, a clean transparent conductive substrate should be used for the preparation of the tin-containing perovskite solar cell. For example, before the process starts, the transparent conductive substrate can be ultrasonically cleaned with isopropyl alcohol or ethanol, and after cleaning and drying or baking, it is reserved for use.

[0016] Step 1: Coat a phenolic derivative-doped PEDOT:PSS solution on the surface of the transparent conductive oxide substrate, and obtain a hole transport layer after annealing treatment;

[0017] Step 2: Coat the perovskite precursor solution on the surface of the PEDOT:PSS film obtained in Step 1. After being treated by solvent extraction processes such as anti-solvent or negative pressure evaporation, anneal to obtain a tin-containing perovskite film;

[0018] Step 3: Coat or evaporate an electron transport layer on the perovskite film described in Step 2;

[0019] Step 4: Evaporate a metal electrode on the electron transport layer to obtain the described tin-containing perovskite solar cell doped with a phenolic derivative hole transport layer.

[0020] Preferably, the deposition methods of the hole transport layer, perovskite active layer, electron transport layer, and metal electrode are each independently selected from at least one of a variety of solution methods, gas phase methods, and large-scale thin film deposition methods such as spin coating, blade coating, vacuum evaporation, magnetron sputtering, atomic layer deposition, and chemical bath deposition.

[0021] Preferably, in Step 1, the hole transport layer adopts a spin coating process. The specific operation is as follows: Spin coat the prepared PEDOT:PSS solution on the substrate at a speed of 1000 - 6000 rpm for 10 - 120 s. After spin coating, transfer the substrate to a heating table for annealing. The annealing temperature is 100°C - 180°C, and the time is 5 - 60 min.

[0022] Preferably, in Step 1, the solution preparation method of the hole transport layer is: Dissolve the phenolic derivative into the PEDOT:PSS solution, and its concentration is 1 - 20 mg mL -1 , and obtain a PEDOT:PSS solution doped with a phenolic derivative by ultrasonic treatment in an ultrasonic cleaner.

[0023] Preferably, in Step 2, the preparation of the tin-containing perovskite active layer adopts a spin coating process and a negative pressure evaporation technique. The specific operation is as follows: Spin coat the perovskite precursor solution on the PEDOT:PSS film at a speed of 1000 - 5000 rpm for 10 - 120 s. Immediately transfer it to a negative pressure evaporation device for vacuum pumping for 10 - 180 s after spin coating, and then perform annealing treatment. The annealing temperature is 60°C - 150°C, and the time is 1 - 60 min.

[0024] Preferably, in Step 2, the preparation method of the tin-containing perovskite precursor solution is: Add raw materials such as SnI2, PbI2, SnF2, MAI, FAI, CsI, etc. according to the molar ratio to a mixed solvent of DMF and DMSO, and stir and dissolve at room temperature to obtain an organic-inorganic hybrid or all-inorganic tin-containing perovskite precursor solution with a concentration of 1.0 - 2.5 M.

[0025] The preparation of inverted tin - containing perovskite thin films using vacuum evaporation technology helps to solve the toxicity problem of traditional anti - solvents and is of great significance for the development of large - area, efficient, stable and low - toxicity photovoltaic devices.

[0026] Preferably, in step three, the preparation method of the electron transport layer is as follows: spin - coat or evaporate the electron transport layer on the perovskite active layer prepared in step two. Taking the PCBM electron transport layer as an example, the solvent of PCBM is chlorobenzene. Dissolve 10 - 50 mg of PCBM powder in 1 mL of chlorobenzene to obtain the electron transport layer solution, and spin - coat it on the perovskite active layer at a speed of 1000 - 6000 rpm for 10 - 60 s.

[0027] Based on the above technical solutions, the concept of the present invention is to introduce phenolic derivatives into the commonly used hole transport layer PEDOT:PSS, while improving the conductivity of the transport layer and passivating the high - density defects at the buried interface of the perovskite layer. First, the phenolic derivatives and the sulfonic acid groups of PSS can form intermolecular hydrogen - bonding interactions, which is beneficial to the stable phase separation of PEDOT and PSS and the conformational rearrangement of PEDOT molecular chains, improving the conductivity of the PEDOT:PSS thin film and the charge transport efficiency of the corresponding PSCs devices. More importantly, the phenolic derivatives have reducing phenolic hydroxyl groups, and the phenolic hydroxyl groups can inhibit the 2+ oxidation of Sn, reduce the interface defects between the PEDOT:PSS / perovskite layer, and help reduce the non - radiative recombination loss at the buried interface. The density of defect states in the tin - containing perovskite thin film optimized by phenolic derivatives decreases, and trap - assisted non - radiative recombination is reduced. Therefore, through the doping of an appropriate amount of phenolic derivatives, the photoelectric conversion efficiency and long - term stability of tin - containing perovskite solar cells are significantly improved.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention proposes a tin - containing perovskite solar cell with a phenolic - derivative - doped hole transport layer. This cell has the advantages of high charge transport efficiency, few interface defects, high photoelectric conversion efficiency and high stability, providing a new idea for solving the development bottleneck of tin - containing perovskite solar cells.

[0030] The phenolic - derivative dopants proposed by the present invention are widely sourced, low - cost and have no side effects, and have good safety when doped into PEDOT:PSS.

[0031] The present invention proposes a preparation method for a tin - containing perovskite solar cell with a phenolic - derivative - doped hole transport layer. This method has simple technology, low cost and good repeatability, and is of great significance for the large - scale production of tin - containing perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below in conjunction with the accompanying drawings.

[0033] Figure 1 It is a schematic diagram of the device structure of a tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer of the present invention;

[0034] Figure 2 It is a conductivity curve graph of the hole transport layer of the perovskite solar cell in Specific Example 1 and Comparative Example 1 of the present invention;

[0035] Figure 3 It is an SEM image of the buried bottom interface of the perovskite solar cell in Specific Example 1 and Comparative Example 1 of the present invention;

[0036] Figure 4 It is an XPS image of the buried bottom interface of the perovskite solar cell in Specific Example 1 and Comparative Example 1 of the present invention;

[0037] Figure 5 It is a PL image of the perovskite active layer of the perovskite solar cell in Specific Example 1 and Comparative Example 1 of the present invention;

[0038] Figure 6 It is an XRD image of the perovskite active layer of the perovskite solar cell in Specific Example 1 and Comparative Example 1 of the present invention;

[0039] Figure 7 It is a J-V curve graph of the perovskite solar cell in Specific Example 1 and Comparative Example 1 of the present invention;

[0040] Figure 8 It is a long-term stability test graph of the perovskite solar cell in Specific Example 1 and Comparative Example 1 of the present invention;

[0041] Figure 9 It is a J-V curve graph of the perovskite solar cell in Specific Example 2 and Comparative Example 1 of the present invention. Detailed implementation manners

[0042] In order to further clarify the technical solution and advantages of the present invention, the technical solution described in the present invention will be further described in detail below in conjunction with the accompanying drawings and specific examples. However, the following examples are only a part of all possible examples of the present invention and are not limited thereto. Any adjustments and improvements made on the premise of the concept of the present invention fall within the protection scope of the present invention.

[0043] The present invention provides a tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer, and the device structure of the perovskite solar cell is as Figure 1As shown in the figure, from bottom to top are a transparent conductive oxide substrate, a hole transport layer doped with natural polyphenol derivatives, a perovskite active layer, an electron transport layer, and a metal electrode. The phenolic derivatives include, but are not limited to, one or more of phenolic hydroxyl-containing compounds such as simple phenolic acids like hydroxybenzoic acids, cinnamic acids, methoxyphenols, flavonoids, tannins, anthocyanins, lignans, etc.

[0044] In the following examples:

[0045] A 2×2 cm FTO conductive glass was ultrasonically cleaned with isopropanol or ethanol solution for 20 min, washed twice repeatedly, and then placed in an 80°C oven until dried. Then, the solvent or impurities that might remain on the FTO substrate were blown dry with a nitrogen gun, and after a 5-min plasma cleaning treatment, it was set aside for use.

[0046] Example 1

[0047] The device structure of a phenolic derivative-doped hole transport layer tin-containing perovskite solar cell in this Example 1 is: FTO / gallic acid-doped PEDOT:PSS / Cs 0.1 FA 0.6 MA 0.3 Pb 0.5 Sn 0.5 I3 / PCBM / BCP / Ag.

[0048] The preparation method of the above-mentioned tin-containing perovskite solar cell doped with gallic acid-doped PEDOT:PSS includes the following steps:

[0049] (1) The gallic acid-doped PEDOT:PSS solution was uniformly spin-coated on the treated FTO conductive glass. The spin-coating process was 4000 rpm for 30 s. After spin-coating, it was transferred to a heating table for annealing at 150°C for 30 min. After annealing and cooling to room temperature, it was transferred to a nitrogen glove box for standby use to obtain the gallic acid-doped PEDOT:PSS hole transport;

[0050] The preparation method of the gallic acid-doped PEDOT:PSS solution is: 7.5 mg of gallic acid was dissolved in 1 mL of PEDOT:PSS solution, and ultrasonicated in an ultrasonic cleaner for 10 min to obtain the gallic acid-doped PEDOT:PSS solution;

[0051] (2) Cs 0.1 FA 0.6 MA 0.3 Pb 0.5 Sn 0.5The I3 perovskite precursor solution was spin-coated on the gallic acid-doped PEDOT:PSS film. The spin-coating process was at 3000 rpm for 30 s. Immediately after spin-coating, it was transferred to a negative pressure evaporation device for 30 s of vacuum pumping, and finally annealed at 100 °C for 10 min in a nitrogen atmosphere to obtain the perovskite film;

[0052] Cs 0.1 FA 0.6 MA 0.3 Pb 0.5 Sn 0.5 The preparation method of the I3 perovskite precursor solution was as follows: SnI2, PbI2, SnF2, MAI, FAI, and CsI were added to the mixed solvent of DMF and DMSO in a molar ratio of 0.5:0.5:0.05:0.3:0.6:0.1, stirred and dissolved at room temperature, and filtered through a 0.22 μm PTFE filter head to obtain an organic-inorganic hybrid tin-lead perovskite precursor solution with a concentration of 2.0 M;

[0053] (3)On the Cs 0.1 FA 0.6 MA 0.3 Pb 0.5 Sn 0.5 The electron transport layer PCBM solution was spin-coated on the I3 perovskite active layer at a spin-coating speed of 2000 rpm for 30 s to obtain the electron transport layer film;

[0054] The preparation method of the PCBM solution was: Weigh 20 mg of PCBM powder and dissolve it in 1 mL of chlorobenzene, and stir magnetically at room temperature until completely dissolved to obtain a 20 mg mL -1 PCBM solution;

[0055] (4)The BCP solution was spin-coated on the PCBM electron transport layer prepared in step (3) at a spin-coating speed of 5000 rpm for 30 s to obtain the BCP layer;

[0056] The preparation method of the BCP solution was: Weigh 0.5 mg of BCP powder and dissolve it in 1 mL of isopropanol, and stir magnetically at room temperature until completely dissolved to obtain a 0.5 mg mL -1 BCP solution;

[0057] (5)The metal Ag electrode of the perovskite solar cell in this example was prepared by thermal evaporation. The specific preparation process was as follows: The device with each functional layer prepared was placed in a mask with a specific pattern and transferred to the evaporation chamber. After pumping to a certain vacuum degree, the metal source was opened, and first evaporated uniformly at a speed of 0.5 Å s -1 at a speed of 35 nm, and then at 2 Å s-1 is evaporated uniformly at a rate of 100 nm to obtain a tin-containing perovskite solar cell with a structure as Figure 1 shown. This example is a preferred example of the present invention and is labeled as Example 1.

[0058] Example 2

[0059] The device structure and preparation method of this example are basically the same as those of Example 1. The difference is that in step (1) of this example, the dopant in PEDOT:PSS is the petroleum-based strong acid isomer of gallic acid - phloroglucinol carboxylic acid (2,4,6-trihydroxybenzoic acid), and the other steps remain unchanged. The specific preparation process and formulation method are as follows:

[0060] The PEDOT:PSS solution doped with phloroglucinol carboxylic acid is spin-coated uniformly on the treated FTO conductive glass. The spin-coating process is 4000 rpm for 30 s. After spin-coating, it is transferred to a heating table for annealing at 150 °C for 30 min. After annealing and cooling to room temperature, it is transferred to a nitrogen glove box for standby to obtain a PEDOT:PSS hole transport layer doped with phloroglucinol carboxylic acid;

[0061] The preparation method of the PEDOT:PSS solution doped with phloroglucinol carboxylic acid is as follows: Dissolve 7.5 mg of phloroglucinol carboxylic acid in 1 mL of PEDOT:PSS solution and ultrasonicate it in an ultrasonic cleaner for 10 min to obtain a PEDOT:PSS solution doped with phloroglucinol carboxylic acid. The tin-containing perovskite solar cell prepared in this example is labeled as Example 2.

[0062] Comparative Example 1

[0063] The device structure and preparation method of this comparative example are basically the same as those of Example 1. The difference is that in step (1) of this comparative example, no dopant is introduced into PEDOT:PSS, and the other steps remain unchanged. The specific preparation process and formulation method are as follows:

[0064] After filtering PEDOT:PSS, the PEDOT:PSS solution is spin-coated uniformly on the FTO conductive glass at a process of 4000 rpm for 30 s. After spin-coating, it is transferred to a heating table for annealing at 150 °C for 30 min. After annealing and cooling to room temperature, it is transferred to a nitrogen glove box for standby to obtain a PEDOT:PSS hole transport layer.

[0065] The tin-lead perovskite solar cell prepared in this comparative example is labeled as Comparative Example 1.

[0066] The tin-lead perovskite solar cells prepared in the above Examples 1 and 2 and Comparative Example 1 were subjected to relevant tests and analyzed according to the results to study the optimization effect of PEDOT:PSS doping on device performance and stability.

[0067] To investigate the electrical properties of the PEDOT:PSS films in Example 1 and Comparative Example 1, devices with FTO / PEDOT:PSS / Ag and FTO / GA-doped PEDOT:PSS / Ag structures were fabricated according to the hole transport layers used in Example 1 and Comparative Example 1, and J-V characteristic tests were carried out in a dark environment, as Figure 2 shown. It can be seen from the J-V curve that the vertical conductivity of the film based on GA-doped PEDOT:PSS is improved compared to the PEDOT:PSS film without any doping. This indicates that there is an interaction between GA and PEDOT:PSS, which can improve the conductivity of the hole transport layer.

[0068] The buried interfaces of the tin-lead perovskite films in Example 1 and Comparative Example 1 were observed by SEM, as Figure 3 shown. Figure 3 (a) and (b) are the microscopic morphologies of the buried interfaces of the perovskite films in Example 1 and Comparative Example 1, respectively. The morphology of the buried interface of the perovskite film grown on the PEDOT:PSS film is wrinkled and there are no obvious grain boundaries, which may be due to the uneven nucleation of the Sn-Pb perovskite film and interface defects. However, the grain boundaries at the buried interface of the perovskite layer grown on the GA-doped PEDOT:PSS film are obvious, and some of the grain sizes reach the micron level. This improvement in the buried interface morphology may be related to the crystallization regulation of GA on the perovskite and the defect passivation effect on the buried interface. The large-sized grains and reduced grain boundary density at the interface can reduce the interface defect density and the recombination probability of carriers at the grain boundaries. This shows that GA doping can improve the interface contact between the perovskite film and the hole transport layer, reduce interface defects, and enhance the overall performance of the device.

[0069] XPS measurement was used to analyze the chemical valence state of the Sn element at the buried interface of the tin-lead perovskite films in Example 1 and Comparative Example 1, as Figure 4 shown. Figure 4 (a) and (b) are the XPS spectra of Sn 3d of the Sn-Pb perovskite films in Example 1 and Comparative Example 1, respectively, where the Sn 3d peak can be decomposed into two separate peaks, which are related to Sn 2+ and Sn 4+ respectively. The content ratio of Sn 4 + / (Sn 2+ +Sn 4+ ) in the control sample is 45.0%, indicating that there is a large amount of Sn 4+ at the buried interface of the control sample. After GA buried interface modification, the content ratio of Sn 4+ / (Sn 2+ +Sn 4+The ratio of () decreased to 39.0%, and the Sn content at the bottom interface decreased. This is because the three reducing hydroxyl groups of GA can inhibit the oxidation of Sn at the interface, reducing the Sn content. At the same time, the carboxyl group of GA can also coordinate with Sn / Pb at the interface, passivating the interface defects between the PEDOT:PSS / perovskite layers, which helps to reduce the non-radiative recombination loss at the interface. 4+ The content of Sn at the bottom interface decreased because the three reducing hydroxyl groups of GA can inhibit the oxidation of Sn at the interface, reducing the Sn content. 2+ Oxidation reduced the Sn content. 4+ At the same time, the carboxyl group of GA can also coordinate with Sn at the interface. 2+ / Pb 2+ Passivate the interface defects between the PEDOT:PSS / perovskite layers, which helps to reduce the non-radiative recombination loss at the interface.

[0070] Carrier dynamics analysis of the tin-lead perovskite thin films in Example 1 and Comparative Example 1 was carried out using PL, as shown below. Figure 5 As shown below. Figure 5 (a) is a schematic diagram of the device structure for PL excitation from the glass substrate side of the perovskite thin film. Figure 5 (b) is the PL test results of Example 1 and Comparative Example 1. The PL peak intensity of the perovskite thin film passivated by GA at the bottom is significantly higher than that of the control film in Comparative Example 1, almost twice as high as the control film. This indicates that the oxidation defects at the bottom interface of Sn are effectively passivated, further confirming that GA reduces the interface defects and inhibits the defect-assisted non-radiative recombination through the strong coordination of the carboxyl group with Sn and the antioxidant effect of the hydroxyl group on Sn. 4+ The oxidation defects at the bottom interface of Sn are effectively passivated, further confirming that GA reduces the interface defects and inhibits the defect-assisted non-radiative recombination through the strong coordination of the carboxyl group with Sn and the antioxidant effect of the hydroxyl group on Sn. 2+ The oxidation defects at the bottom interface of Sn are effectively passivated, further confirming that GA reduces the interface defects and inhibits the defect-assisted non-radiative recombination through the strong coordination of the carboxyl group with Sn and the antioxidant effect of the hydroxyl group on Sn. 2+ The oxidation defects at the bottom interface of Sn are effectively passivated, further confirming that GA reduces the interface defects and inhibits the defect-assisted non-radiative recombination through the strong coordination of the carboxyl group with Sn and the antioxidant effect of the hydroxyl group on Sn.

[0071] The crystallization quality and crystal structure changes of the perovskite thin films in Example 1 and Comparative Example 1 were characterized based on XRD measurements, as shown below. Figure 6 Characteristic diffraction peaks corresponding to the (110) and (220) crystal planes of Sn-Pb perovskite appeared near 14.1° and 28.4° for the samples under both conditions, indicating that the crystal structure of the perovskite was not changed by GA doping. In addition, the intensities of the (110) and (220) diffraction peaks of the perovskite thin films prepared based on the GA-doped PEDOT:PSS substrate increased compared to Comparative Example 1, and the full width at half maximum (FWHM) of the peaks decreased compared to Comparative Example 1. These results indicate that the crystallization degree of the Sn-Pb perovskite thin films was improved due to the passivation of the bottom interface by GA, which improved the quality of the Sn-Pb perovskite thin films.

[0072] Figure 7 The J-V characteristic curves of the Sn-Pb perovskite solar cells described in Example 1 and Comparative Example 1 are shown below. By comparison, it was found that the device with GA-doped PEDOT:PSS as the hole transport layer in Example 1 achieved a higher power conversion efficiency. The best PCE of the device was 21.70%, V was 0.871 V, and J was 31.11 mA cm. OC V was 0.871 V, SC J was 31.11 mA cm -2, FF is 80.1%. For the device with PEDOT:PSS as the hole transport layer in Comparative Example 1, the best PCE is only 18.45%, V OC is 0.816 V, J SC is 30.78 mA cm -2 , and FF is 73.48%. It can be seen that GA doping can effectively passivate interface defects, improve the extraction and transport efficiency of hole carriers, and significantly improve the photovoltaic performance of the device.

[0073] Figure 8 shows the long-term stability test results of the Sn-Pb perovskite solar cells described in Example 1 and Comparative Example 1 under a nitrogen atmosphere. It can be seen that the device based on GA doping maintained 96% of the initial efficiency after 2424 hours of storage, while the undoped device only retained 60% of the initial efficiency after the same time, confirming that the GA doping passivation of the buried interface strategy improved the long-term stability of the corresponding device.

[0074] Figure 9 Figure 13 shows the J-V characteristic curves of the Sn-Pb perovskite solar cells described in Example 2 and Comparative Example 1. By comparison, it is found that the device with phloroglucinol formic acid doped PEDOT:PSS as the hole transport layer in Example 2 achieved a higher power conversion efficiency. The best PCE of the device is 19.88%, V OC is 0.827 V, J SC is 31.39 mA cm -2 , and FF is 76.57%. For the device with PEDOT:PSS as the hole transport layer in Comparative Example 1, the best PCE is only 18.45%, V OC is 0.816 V, J SC is 30.78 mA cm -2 , and FF is 73.48%. It can be seen that the introduction of phloroglucinol formic acid can improve the conductivity of PEDOT:PSS and the extraction and transport efficiency of hole carriers, effectively passivate interface defects, optimize interface contact, and significantly improve the current density and fill factor of the device after phloroglucinol formic acid doping.

[0075] The above are only the preferred specific embodiments of the present invention, and do not limit the protection scope of the present invention. It should be understood that although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art can still make many modifications and changes according to the technical solutions described in the above embodiments. Therefore, all technical solutions obtained through non-creative labor such as logical analysis, reasoning, or limited experiments based on the design principle of the present invention should fall within the protection scope of the present invention.

Claims

1. A tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer, characterized in that: The device structure of the perovskite solar cell is of the p-i-n type, and from bottom to top, it is successively a transparent conductive oxide substrate, a hole transport layer, a perovskite active layer, an electron transport layer, and a metal electrode. The hole transport layer is a PEDOT:PSS layer doped with a phenolic derivative.

2. A tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer according to claim 1, characterized in that: The phenolic derivatives include, but are not limited to, one or more of phenolic hydroxyl group-containing compounds such as simple phenolic acids like hydroxybenzoic acids, cinnamic acids, methoxyphenols, flavonoids, tannins, anthocyanins, lignans, etc. The molecular characteristics of phenolic derivatives are as follows: having a carbon chain structure of C6-C x , where C6 is a benzene ring and C x is a benzene ring substituent containing carbon, and 1-3 hydroxyl groups are connected to the benzene ring. Among them, when the number of phenolic hydroxyl groups is 1, the phenolic derivatives include but are not limited to 4-hydroxybenzoic acid, 4-hydroxybenzonitrile, ferulic acid (3-methoxy-4-hydroxycinnamic acid), etc.; when the number of phenolic hydroxyl groups is 2, the phenolic derivatives include but are not limited to protocatechuic acid (3,4-dihydroxybenzoic acid), 2,5-dihydroxybenzoic acid, caffeic acid (3,4-dihydroxycinnamic acid), 2,5-dihydroxycinnamic acid, 3,4-dihydroxybenzamide, 2,5-dihydroxybenzamide, 2,5-dihydroxybenzonitrile, 3,4-dihydroxybenzaldehyde oxime, etc., compounds and their derivatives with two hydroxyl groups in the ortho or para positions of the benzene ring; when the number of phenolic hydroxyl groups is 3, the phenolic derivatives include but are not limited to gallic acid (3,4,5-trihydroxybenzoic acid), 2,4,6-trihydroxybenzoic acid, 2,3,4-trihydroxybenzoic acid, 2,4,5-trihydroxybenzoic acid, methyl 3,4,5-trihydroxybenzoate, ethyl 3,4,5-trihydroxybenzoate, propyl 3,4,5-trihydroxybenzoate, 3,4,5-trihydroxybenzamide, 3,4,5-trihydroxybenzohydrazide, etc., compounds and their derivatives with at least two hydroxyl groups in the ortho position of the benzene ring. In addition, when the number of phenolic hydroxyl groups ≥ 4, the phenolic derivatives are usually complex polymers or flavonoid skeletons, including but not limited to ellagic acid, tannic acid, catechin, tea polyphenols, etc.

3. A tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer according to claim 1, characterized in that: The hole transport layer is at least one of various types of PEDOT:PSS such as PEDOT:PSS 4083, PEDOT:PSS PH1000, etc.

4. A tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer according to claim 1, wherein: The perovskite active layer is at least one of all organic-inorganic hybrid perovskites or all-inorganic perovskite materials containing metal tin cations, and the structural formula is ABX3.

5. A tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer according to claim 1, characterized in that: The solvent of the perovskite active layer can be, but is not limited to, one or several of various organic solvents such as N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone (GBL), γ-valerolactone (GVL), N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAC), N,N-dimethylpropyleneurea (DMPU), acetonitrile, 2-mercaptoethanol (ME), 1,3-dimethyl-2-imidazolidinone (DMI), etc., or ionic liquids such as methylammonium formate, methylammonium acetate, methylammonium propionate, methylammonium butyrate, dimethylammonium acetate. Taking dissolution in DMF and DMSO as an example, the volume ratio range of DMF and DMSO solvents can be, but is not limited to, 1:19 - 19:1, and the preferred range is 19:1 - 1:

1.

6. A tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer according to claim 1, characterized in that: The substrate of the tin-containing perovskite solar cell can be, but is not limited to, at least one of flexible or rigid substrates such as glass coated with a transparent conductive oxide film, silicon wafers, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), etc. The transparent conductive oxide film can be, but is not limited to, at least one of oxide thin films such as indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), indium-doped zinc oxide (IZO), fluorine-doped tin oxide (FTO), indium tungsten oxide (IWO), indium cerium oxide (ICO), etc.

7. A tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer according to claim 1, characterized in that: The electron transport layer of the tin-containing perovskite solar cell can be, but is not limited to, fullerenes and their derivatives, such as C 60 , PCBM ([6,6]-phenyl-C61-butyric acid methyl ester), ICBA (indole-C60 bisadduct), etc., or at least one of non-fullerene materials, such as n-type conjugated polymer materials, n-type organic small molecules, and n-type metal oxides.

8. A tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer according to claim 1, characterized in that: The metal electrode of the tin-containing perovskite solar cell can be, but is not limited to, at least one of various metal electrodes such as Au, Ag, Cu, Bi, etc.

9. The preparation method of a tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer according to claim 1, characterized in that, It includes the following steps: Step 1: Coat a PEDOT:PSS solution doped with a phenolic derivative on the surface of the transparent conductive oxide substrate, and obtain a hole transport layer after annealing treatment; Step 2: Coat a perovskite precursor solution on the surface of the PEDOT:PSS film obtained in Step 1, and obtain a tin-containing perovskite film after annealing through a solvent extraction process such as anti-solvent or negative pressure evaporation; Step 3: Coat or evaporate an electron transport layer on the perovskite film described in Step 2; Step 4: Evaporate a metal electrode on the electron transport layer to obtain the tin-containing perovskite solar cell with a hole transport layer doped with a phenolic derivative; Preferably, the deposition methods of the hole transport layer, the perovskite active layer, the electron transport layer, and the metal electrode are each independently selected from at least one of various solution methods, gas phase methods, and large-scale thin film deposition methods such as spin coating, blade coating, vacuum evaporation, spraying, magnetron sputtering, and atomic layer deposition.

10. Application of a tin-containing perovskite solar cell with a phenolic derivative-doped hole transport layer and a preparation method thereof in the field of optoelectronics according to claim 1.

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