Method for improving efficiency and stability of perovskite solar cell and perovskite solar cell

Abstract

The application relates to a method for improving the efficiency and stability of a perovskite solar cell, which comprises the following steps: preparing an organic interface layer on a charge transport layer, and then preparing a perovskite active layer on the organic interface layer, wherein the charge transport layer is an inorganic p-type semiconductor hole transport layer or an inorganic n-type semiconductor electron transport layer, and the organic interface material in the organic interface layer is selected from one of the following structures. The method based on the application solves the problems of poor efficiency and stability of the perovskite solar cell in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, specifically relating to a method for improving the efficiency and stability of perovskite solar cells and a perovskite solar cell. Background Technology

[0002] Solar energy, with its advantages of being widely available, inexhaustible, clean, and safe, is highly favored. Large-scale utilization of clean and renewable solar energy is of great significance for optimizing energy consumption structure and reducing environmental pollution. Solar cells, which directly convert light energy into electrical energy using the photovoltaic effect, provide an effective way to utilize solar energy and have therefore been a research hotspot in the photovoltaic field both domestically and internationally. Although the current market value of photovoltaic production is growing at a rate of 30% annually, the total installed capacity still accounts for less than 1% of global energy consumption.

[0003] Since their initial report in 2009, organometal halide perovskite solar cells have made rapid progress due to their advantages such as high carrier mobility, high absorption coefficient, tunable bandgap, simple fabrication process, and low cost. Currently, their photoelectric conversion efficiency has reached an astonishing 25.7%. This ultra-high efficiency and low cost are driving the commercialization of perovskite solar cells, potentially breaking the current monopoly of silicon solar cells and becoming a strong competitor in the next generation of photovoltaic technology. Despite these numerous advantages, perovskite solar cells still face challenges in reconciling efficiency and stability with large-area scaling effects. Taking nickel oxide, an inorganic p-type hole transport material commonly used in pin-type perovskite solar cells, as an example, perovskite solar cells based on nickel oxide pin structures have significant stability advantages and have shown good application results in single-junction perovskite solar cells and tandem solar cells. However, they face the problem of insufficient stability or low cell efficiency. For example, most of the reported efficiencies of nickel oxide-based pin-type perovskite solar cells are below 22%. Nip-type perovskite solar cells with tin dioxide as the electron transport layer have achieved efficiencies exceeding 25%, but they face the problem of insufficient stability. The main challenges to achieving a comprehensive improvement in efficiency and stability for the above two cell structures are the low open-circuit voltage, high non-radiative recombination loss, and interface reactions. These losses are determined by the charge-selective contact interface. Typically, the interface between metal-oxide-semiconductor (MOS) charge transport materials and perovskites contains numerous defects. This is because the strong surface dipole moment of MOS induces ions from the perovskite precursor solution to adhere to the surface of the semiconductor oxide, generating numerous vacancy defects at grain boundaries. These defects not only act as nonradiative recombination centers leading to efficiency loss mechanisms but also create rapid channels for moisture or oxygen penetration and accelerate interfacial reactions, which is detrimental to the stability of perovskite devices. Furthermore, interfacial effects include not only the impact of interface defects on power conversion efficiency but also the impact of ion diffusion and the resulting chemical reactions and degradation on device stability. For example, during aging, ions in the perovskite diffuse to the charge transport contact interface and accumulate. This charge accumulation affects interfacial band alignment and device efficiency, causing hysteresis, which is one of the main reasons affecting device stability. Additionally, poor interfacial electrical contact makes it difficult to extract interfacial carriers, leading to interfacial charge accumulation and capacitance effects, increasing hysteresis and interfacial recombination, thereby reducing the device's open-circuit voltage. Therefore, improving these interfacial properties is crucial for the efficiency and stability of perovskite solar cells.

[0004] Organic molecules possess strong designability; through rational molecular structure design, molecular energy levels and molecular configurations can be controlled to achieve specific functions. Currently, organic molecules are frequently used to modify the inorganic semiconductor layer in perovskite solar cells or directly as charge transport materials. Small organic molecules with interface modification capabilities typically contain an anchoring group, such as carboxylic acids or phosphorous acids. The interaction between these anchoring groups and the substrate ensures that the small organic molecule conformally covers the substrate. Furthermore, the host structure of most small organic molecules is often an aromatic heterocycle, such as carbazole or triphenylamine derivatives. These organic molecules can interact with the perovskite layer, passivating the interface and thus reducing interfacial carrier transport losses, achieving great success in high-performance photovoltaic devices. For example, an inverse perovskite solar cell based on ([2-(9H-carbazole-9-yl)ethyl)phosphonic acid)(2PACz) as the interface hole layer achieved an efficiency as high as 24.3% and passed the industrial "double 85" test (perovskite solar cells retain more than 95% of their original efficiency after aging at 85 degrees Celsius and 85% humidity for 1000 hours); ([4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz) was used as the interface hole material for wide-bandgap perovskite solar cells, helping to achieve a certified efficiency breakthrough of 29% for perovskite / silicon tandem cells; in addition, ([2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid)(MeO-2PACz) was used as the interface hole material for wide-bandgap perovskite solar cells. A mixed solution of 2PACz and 2PACz was used as an interface modifier for nickel oxide substrates, significantly reducing defects at the perovskite / nickel oxide interface and helping to achieve a certified efficiency of 26.4% for all-perovskite stacks. However, these commonly used small organic molecules are relatively expensive, or the core materials required for their synthesis are relatively costly; moreover, these molecules rely solely on single anchor groups to interact with the perovskite, which is relatively weak. During long-term operation, the perovskite / modified molecule interface may experience delamination, weakened interactions, and other potential adverse factors. Therefore, developing interface materials that can effectively passivate interface defects and improve stability and efficiency, thereby achieving a comprehensive improvement in the efficiency and stability of perovskite solar cells, is of great significance for the further development and commercial production of perovskite solar cells. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a method for improving the efficiency and stability of perovskite solar cells and a perovskite solar cell, so as to solve the problem of poor efficiency and stability of perovskite solar cells in the prior art.

[0006] The specific solution provided by this invention is as follows:

[0007] This invention provides a method for improving the efficiency and stability of perovskite solar cells. First, an organic interface layer is formed on a charge transport layer, and then a perovskite active layer is formed on the organic interface layer. The charge transport layer is an inorganic p-type semiconductor hole transport layer or an inorganic n-type semiconductor electron transport layer, and the organic interface material in the organic interface layer is selected from one of the following structures:

[0008]

[0009] Based on the technical solution of the present invention, the following beneficial effects are achieved:

[0010] (1) In this invention, phenyl, triphenylamine, and triphenylamine triazine derivatives, which are inexpensive, have good solubility, good film-forming properties, excellent chemical stability, and high hole mobility, are selected as the main structure of the interface modification material. At the same time, multi-anchor groups (three carboxyl groups or three amino groups) are introduced into these main structures to form Δ-type tri-anchor structure interface modification molecules. When the Δ-type tri-anchor structure interface modification molecules are applied to the perovskite / inorganic charge transport layer interface, the multi-anchor groups enable the modification molecules to interact with both the inorganic charge transport layer and the perovskite at the same time. Compared with common organic modification molecules with only one anchor group, its anchoring ability is stronger, resulting in better bonding performance and superior stability between the perovskite / inorganic charge transport layer interface. In addition, the presence of Δ-type tri-anchor groups also enables the modification molecules to form good electrical coupling with the charge transport layer and the perovskite, effectively passivating interface defects and promoting carrier transport. The interface modification molecule based on the Δ-type three-anchor structure proposed in this invention can be used to modify the interface of the charge transport layer in perovskite solar cells, effectively passivating perovskite buried interface defects, promoting the transport of interface charge carriers, and thus improving the photovoltaic performance of perovskite solar cells.

[0011] Based on the above technical solution, the present invention can be further improved as follows:

[0012] Furthermore, the preparation of the organic interface layer includes the following steps:

[0013] The organic interface material is dissolved in ethanol, isopropanol or N,N-dimethylformamide to obtain an organic interface material solution with a concentration of 0.1-10 mg / mL. The organic interface material solution is then coated onto the charge transport layer by spin coating, blade coating, spraying, slot coating or immersion. Finally, the layer is annealed at an annealing temperature of 70-150°C for 5-60 minutes.

[0014] The present invention also provides a perovskite solar cell, which is a pin-type perovskite solar cell. The pin-type perovskite solar cell includes: a transparent conductive oxide substrate, an inorganic p-type semiconductor hole transport layer, a perovskite active layer, and an organic interface layer disposed between the inorganic p-type semiconductor hole transport layer and the perovskite active layer.

[0015] Alternatively, the perovskite solar cell is a nip-type perovskite solar cell, which includes: a transparent conductive oxide substrate, an inorganic n-type semiconductor electron transport layer, a perovskite active layer, and an organic interface layer disposed between the inorganic n-type semiconductor electron transport layer and the perovskite active layer.

[0016] The material of the organic interface layer is selected from one of the following structures:

[0017]

[0018] Furthermore, the pin-type perovskite solar cell includes, from bottom to top, a transparent conductive oxide substrate, an inorganic p-type semiconductor hole transport layer, an organic interface layer, a perovskite active layer, an electron transport layer, a hole blocking layer, and an electrode layer; the nip-type perovskite solar cell includes, from bottom to top, a transparent conductive oxide substrate, an inorganic n-type semiconductor electron transport layer, an organic interface layer, a perovskite active layer, a hole transport layer, and an electrode layer.

[0019] Furthermore, the inorganic p-type semiconductor hole transport layer material is selected from one of nickel oxide, doped nickel oxide, cuprous thiocyanate, or cuprous chromate.

[0020] Furthermore, the inorganic n-type semiconductor electron transport layer material is selected from either tin dioxide or titanium dioxide.

[0021] Furthermore, the perovskite active layer material has an ABX3 structure, wherein A is selected from methylammonium, formamidinium, and Cs. + One or more of them, B is selected from Pb 2+ Sn 2+ One or two of them, X is selected from I - ,Br - Cl - One or more of them.

[0022] Furthermore, the electron transport layer material is selected from [6,6]-phenyl-C71-butyrate isomethyl ester, C 60 Or C 60 One of the derivatives.

[0023] Furthermore, the hole transport layer material is selected from 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene or cuprous thiocyanate.

[0024] Furthermore, the electrode layer is a single-layer structure or a double-layer structure. The material of the single-layer structure is selected from silver, gold, copper, chromium, indium tin oxide, aluminum-doped zinc oxide, or tungsten-doped indium oxide. The double-layer structure is selected from bismuth-copper double-layer structure, bismuth-gold double-layer structure, bismuth-silver double-layer structure, chromium-copper double-layer structure, chromium-gold double-layer structure, or chromium-silver double-layer structure.

[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a pin perovskite solar cell according to an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the structure of a nip perovskite solar cell according to another embodiment of the present invention.

[0028] Figure 3 This is a scanning electron microscope cross-sectional view of the pin perovskite solar cell in Embodiment 1 of the present invention.

[0029] Figure 4 This is a scanning electron microscope cross-sectional view of the nip perovskite solar cell in Embodiment 6 of the present invention.

[0030] Figure 5 This is a current density-voltage curve for a perovskite solar cell.

[0031] Figure 6 The image shows the contact angle test results of the perovskite solution on the inorganic charge transport layer.

[0032] Figure 7 This is the steady-state fluorescence spectrum of the perovskite film.

[0033] Figure 8 This is the transient fluorescence spectrum of the perovskite film.

[0034] Figure 9 This is a graph showing the thermal stability test results for perovskite solar cells.

[0035] Appendix Figure 1-2 The component names represented by each number are as follows:

[0036] 1. Transparent conductive substrate;

[0037] 21. Inorganic p-type semiconductor hole transport layer; 22. Inorganic n-type semiconductor electron transport layer;

[0038] 3. Organic interface layer;

[0039] 4. Perovskite active layer;

[0040] 51. Electron transport layer; 52. Hole transport layer

[0041] 6. Electrode layer;

[0042] 7. Cavity blocking layer. Detailed Implementation

[0043] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0044] The method for improving the efficiency and stability of perovskite solar cells based on embodiments of the present invention first prepares an organic interface layer on a charge transport layer, and then prepares a perovskite active layer on the organic interface layer. The charge transport layer is an inorganic p-type semiconductor hole transport layer or an inorganic n-type semiconductor electron transport layer, and the organic interface material in the organic interface layer is selected from one of the following structures:

[0045]

[0046] This invention modifies the surface of the charge transport layer (inorganic p-type semiconductor hole transport layer or inorganic n-type semiconductor electron transport layer) with organic small molecules of the above-mentioned Δ-type three-anchor structure. This effectively passivates perovskite buried interface defects, enhances interfacial interactions, promotes the carrier transport efficiency at the interface between the perovskite layer and the charge transport layer, and improves the photoelectric performance and stability of the prepared perovskite solar cell. It solves the problems of insufficient cell interface stability and low charge transport efficiency in the prior art, and provides a new approach for preparing high-efficiency and stable perovskite solar cells.

[0047] The method for improving the efficiency and stability of perovskite solar cells based on embodiments of the present invention includes the following steps in the preparation of the organic interface layer:

[0048] The organic interface material is dissolved in ethanol, isopropanol or N,N-dimethylformamide to obtain an organic interface material solution with a concentration of 0.1-10 mg / mL. The organic interface material solution is then coated onto the charge transport layer by spin coating, blade coating, spraying, slot coating or immersion. Finally, the layer is annealed at an annealing temperature of 70-150°C for 5-60 minutes.

[0049] Based on the perovskite solar cell of the present invention, the perovskite solar cell is a pin-type perovskite solar cell, such as... Figure 1 The perovskite solar cell with the pin-type structure includes: a transparent conductive oxide substrate 1, an inorganic p-type semiconductor hole transport layer 21, a perovskite active layer 4, and an organic interface layer 3 disposed between the inorganic p-type semiconductor hole transport layer 21 and the perovskite active layer 4.

[0050] Alternatively, the perovskite solar cell is a nip-type perovskite solar cell, and Figure 2 As shown, the nip-type perovskite solar cell includes: a transparent conductive oxide substrate 1, an inorganic n-type semiconductor electron transport layer 22, a perovskite active layer 4, and an organic interface layer 3 disposed between the inorganic n-type semiconductor electron transport layer 22 and the perovskite active layer 4.

[0051] The material of the organic interface layer is selected from one of the following structures:

[0052]

[0053] The perovskite solar cell based on the embodiments of the present invention includes, from bottom to top, a transparent conductive oxide substrate 1, an inorganic p-type semiconductor hole transport layer 21, an organic interface layer 3, a perovskite active layer 4, an electron transport layer 51, a hole blocking layer 7, and an electrode layer 6; and the nip-type perovskite solar cell includes, from bottom to top, a transparent conductive oxide substrate 1, an inorganic n-type semiconductor electron transport layer 22, an organic interface layer 3, a perovskite active layer 4, a hole transport layer 52, and an electrode layer 6.

[0054] Preferably, in the perovskite solar cell based on the embodiments of the present invention, the inorganic p-type semiconductor hole transport layer material is selected from one of nickel oxide, doped nickel oxide, cuprous thiocyanate, or cuprous chromate.

[0055] Preferably, when the inorganic p-type semiconductor hole transport layer material is nickel oxide or doped nickel oxide, the p-type semiconductor hole transport layer is prepared by magnetron sputtering of a nickel oxide target onto a transparent conductive oxide substrate, or by spraying a pyrolytic nickel oxide precursor solution onto a transparent conductive oxide substrate and sintering the nickel oxide target coated with the nickel oxide precursor at high temperature, or by spin-coating nickel oxide nano-ink onto a transparent conductive oxide substrate; when the inorganic p-type semiconductor hole transport layer material is cuprous thiocyanate or cuprous chromate, the p-type semiconductor hole transport layer is prepared by spin-coating nanomaterials and then sintering at high temperature.

[0056] Preferably, in the perovskite solar cell based on the embodiments of the present invention, the inorganic n-type semiconductor electron transport layer material is selected from tin dioxide or titanium dioxide.

[0057] Preferably, in the perovskite solar cell based on the embodiments of the present invention, the perovskite active layer material has an ABX3 structure, wherein A is selected from methylammonium, formamidinium, and Cs. + One or more of them, B is selected from Pb 2+ Sn 2+ One or two of them, X is selected from I - ,Br - Cl - One or more of them.

[0058] Preferably, in the perovskite solar cell based on the embodiments of the present invention, the electron transport layer material is selected from [6,6]-phenyl-C71-butyrate isomethyl ester, C 60 Or C 60 One of the derivatives.

[0059] Preferably, in the perovskite solar cell based on the embodiments of the present invention, the hole transport layer material is selected from 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene or cuprous thiocyanate.

[0060] Preferably, in the perovskite solar cell based on the embodiments of the present invention, the electrode layer is a single-layer structure or a double-layer structure. The material of the single-layer structure is selected from silver, gold, copper, chromium, indium tin oxide, aluminum-doped zinc oxide, or tungsten-doped indium oxide. The double-layer structure is selected from bismuth-copper double-layer structure, bismuth-gold double-layer structure, bismuth-silver double-layer structure, chromium-copper double-layer structure, chromium-gold double-layer structure, or chromium-silver double-layer structure.

[0061] Preferably, the transparent conductive oxide substrate is selected from indium tin oxide (ITO) or fluorine-doped tin oxide conductive glass (FTO).

[0062] Example 1

[0063] A PIN perovskite solar cell includes, from bottom to top, a transparent conductive oxide substrate, an inorganic p-type semiconductor hole transport layer, an organic interface layer, a perovskite active layer, an electron transport layer, a hole blocking layer, and an electrode layer; wherein, the transparent conductive oxide substrate is FTO glass, the inorganic p-type semiconductor hole transport layer is made of NiMgLiO, the organic interface layer is made of 1,3,5-phenyltricarboxylic acid, and the perovskite active layer is made of (Cs) 0.15 FA 0.85 )Pb(I 0.95 Br 0.053. The electron transport layer is made of isomethyl [6,6]-phenyl-C71-butyrate (PCBM), the hole blocking layer is made of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and the electrode layer is made of silver. The thicknesses of the inorganic p-type semiconductor hole transport layer, organic interface layer, perovskite active layer, electron transport layer, hole blocking layer, and electrode layer are 20 nm, 5 nm, 450 nm, 30 nm, 3 nm, and 80 nm, respectively.

[0064] The fabrication steps of the pin perovskite solar cell are as follows:

[0065] (1) Preparation of inorganic p-type semiconductor hole transport layer: magnesium acetate tetrahydrate and lithium acetate were added to a mixed solution of nickel acetylacetonate, acetonitrile and ethanol to obtain NiMgLiO precursor solution. The volume ratio of acetonitrile to ethanol in the NiMgLiO precursor solution was 95:5, the atomic molar ratio of Ni:Mg:Li was 80:15:5, and the total metal ion concentration was 0.02M. The NiMgLiO precursor solution was sprayed onto a transparent conductive oxide substrate and annealed at 570℃ for 30 minutes to obtain NiMgLiO hole transport layer.

[0066] (2) Preparation of Δ-type organic interface layer: 1,3,5-benzenetricarboxylic acid was dissolved in ethanol to prepare a 1,3,5-benzenetricarboxylic acid solution with a concentration of 0.5 mg / mL. The 1,3,5-benzenetricarboxylic acid solution was then coated onto the NiMgLiO hole transport layer. The solution was then annealed at 120℃ for 20 min to obtain the 1,3,5-benzenetricarboxylic acid organic interface layer.

[0067] (3) Preparation of the perovskite active layer: The perovskite active layer was prepared by a one-step spin coating method (spin coating parameters: rotation speed 6000 rpm, acceleration: 3000 rpm, spin coating time: 60 seconds). The specific steps included: dissolving FAI (0.2193 g), PbI2 (0.6915 g), and CsBr (0.0479 g) in a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO was 4:1) to obtain CsBr. 0.15 FA 0.85 Pb(I 0.95 Br 0.05 )3 Perovskite precursor solution (Cs 0.15 FA 0.85 Pb(I 0.95 Br 0.05(3) The concentration was 1.5M. Then, the perovskite precursor solution was spin-coated onto the 1,3,5-benzenetricarboxylic acid organic interface layer to obtain the perovskite precursor solution layer. At 15 seconds into the spin-coating step, the perovskite precursor solution layer was rapidly washed with 200 μL of chlorobenzene. After spin-coating, it was annealed on a hot plate at 150°C for 20 minutes to obtain Cs. 0.15 FA 0.85 Pb(I 0.95 Br 0.05 3. Perovskite active layer.

[0068] (4) Preparation of electron transport layer: PCBM solution (concentration of 20 mg / mL) -1 The solvent is chlorobenzene) spin-coated (spin-coating parameters: spin-coating speed of 3000 rpm, spin-coating time of 30 seconds) onto the perovskite active layer, and then annealed at 70°C for 10 minutes to obtain the PCBM electron transport layer.

[0069] (5) Preparation of hole blocking layer: Spin-coating saturated BCP solution (spin-coating parameters: spin-coating speed of 6000 rpm, spin-coating time of 30 seconds) onto PCBM electron transport layer, and then annealing at 70°C for 10 minutes.

[0070] (6) Electrode layer preparation: In a vacuum evaporation machine, at a vacuum degree of 3×10 -4 Below Pa, The Ag electrode layer is obtained by thermally evaporating metallic Ag at a certain rate.

[0071] Example 2

[0072] A pin perovskite solar cell, the same as in Example 1, except that the organic interface layer material is 4,4,4-triphenylamine tricarboxylate.

[0073] Example 3

[0074] A pin perovskite solar cell, the same as in Example 1, except that the organic interface layer material is 1,3,5-tris(4-aminophenyl)benzene.

[0075] Example 4

[0076] A pin perovskite solar cell, the same as in Example 1, differs only in that: the material of the organic interface layer is 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine; in step (2), 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine is dissolved in DMF to prepare a mixed solution with a concentration of 1 mg / mL, and then the mixed solution is coated on the NiMgLiO hole transport layer, and then annealed at an annealing temperature of 150°C for 30 min to obtain the organic interface layer.

[0077] Example 5

[0078] A pin perovskite solar cell, the same as in Example 1, differs only in that: the material of the organic interface layer is 2,4,6-tris(4-aminophenyl)-1,3,5-triazine; in step (2), 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is dissolved in DMF to prepare a mixed solution with a concentration of 1 mg / mL of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and then the mixed solution is coated on the NiMgLiO hole transport layer, and then annealed at an annealing temperature of 100°C for 10 min to obtain the organic interface layer.

[0079] Example 6

[0080] A nip perovskite solar cell includes, from bottom to top, a transparent conductive oxide substrate, an inorganic n-type semiconductor electron transport layer, a perovskite active layer, a hole transport layer, and an electrode layer. The transparent conductive oxide substrate is ITO glass, the inorganic n-type semiconductor electron transport layer is made of tin dioxide, the organic interface layer is made of 1,3,5-phenyltricarboxylic acid, and the perovskite active layer is made of (FAPbI3). 0.95 (MAPbBr3) 0.05 The hole transport layer is made of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (spiro-OMeTAD), and the electrode layer is made of silver. The thicknesses of the inorganic n-type semiconductor hole transport layer, the organic interface layer, the perovskite active layer, the hole transport layer, and the electrode layer are 20 nm, 5 nm, 500 nm, 200 nm, and 150 nm, respectively.

[0081] The fabrication process of nip perovskite solar cells is as follows:

[0082] (1) Preparation of inorganic n-type semiconductor electron transport layer: SnO2 nanoparticle dispersion (SnO2 nanoparticle mass percentage of 2.67%, dispersant is water) was spin-coated onto ITO glass substrate at 4000 rpm, and then annealed in ambient air at 150°C for 30 minutes.

[0083] (2) Preparation of Δ-type organic interface layer: SnO2 film was treated with UV machine for 10 minutes, then 1,3,5-benzenetricarboxylic acid was dissolved in ethanol to prepare a 1,3,5-benzenetricarboxylic acid solution with a concentration of 0.5 mg / mL. The 1,3,5-benzenetricarboxylic acid solution was then coated on SnO2 electron transport layer. Finally, the 1,3,5-benzenetricarboxylic acid organic interface layer was obtained by annealing at 120℃ for 20 min.

[0084] (3) Preparation of the perovskite active layer: The perovskite active layer was prepared by a one-step spin coating method (spin coating parameters: 6000 rpm, acceleration: 3000 rpm, spin coating time: 60 seconds). The specific steps included: dissolving FAI (0.2193 g), PbI2 (0.6915 g), and CsBr (0.0479 g) in a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO was 4:1) to prepare CsBr. 0.15 FA 0.85 Pb(I 0.95 Br 0.05 )3 Perovskite precursor solution (Cs 0.15 FA 0.85 Pb(I 0.95 Br 0.05 (3) The concentration was 1.5M. Then, the perovskite precursor solution was spin-coated onto the 1,3,5-benzenetricarboxylic acid organic interface layer to obtain the perovskite precursor solution layer. At 15 seconds into the spin-coating step, the perovskite precursor solution layer was rapidly washed with 200 μL of chlorobenzene. After spin-coating, it was annealed on a hot plate at 150°C for 20 minutes to obtain Cs. 0.15 FA 0.85 Pb(I 0.95 Br 0.05 3. Perovskite active layer.

[0085] (4) Hole transport layer preparation: 260 mg of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was dissolved in 1 ml of acetonitrile to obtain a LiTFSI solution. Then, 90 mg of spiro-OMeTAD, 44 μL of LiTFSI solution, and 37 μL of 4-tert-butylpyridine were dissolved in 1 ml of chlorobenzene to form a spiro-OMeTAD solution. The spiro-OMeTAD solution was then spin-coated onto Cs at a rotation speed of 1500 rpm. 0.15 FA 0.85 Pb(I 0.95 Br 0.05 The perovskite active layer was then oxidized overnight in a drying cabinet (25°C, 1% humidity) to obtain the spiro-OMeTAD hole transport layer.

[0086] (5) Electrode layer preparation: In a vacuum evaporation machine, at a vacuum degree of 3×10 -4 Below Pa, The Ag electrode layer is obtained by thermal evaporation of metallic Ag at a certain rate.

[0087] Example 7

[0088] A nip perovskite solar cell is the same as in Example 6, except that the organic interface layer material is 4,4,4-triphenylamine tricarboxylate.

[0089] Example 8

[0090] A nip perovskite solar cell is the same as in Example 6, except that the organic interface layer material is 1,3,5-tris(4-aminophenyl)benzene.

[0091] Example 9

[0092] A type of nip perovskite solar cell is the same as in Example 6, except that the organic interface layer is made of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine. The preparation process of the organic interface layer is as follows: 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine is dissolved in DMF to prepare a mixed solution with a concentration of 1 mg / mL. The mixed solution is then coated on a tin dioxide electron transport layer, and then annealed at 150°C for 30 min to obtain the 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine organic interface layer.

[0093] Example 10

[0094] A nip perovskite solar cell is identical to that in Example 6, except that the organic interface layer is made of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine. The preparation process of the organic interface layer is as follows: 2,4,6-tris(4-aminophenyl)-1,3,5-triazine is dissolved in DMF to prepare a mixed solution with a concentration of 1 mg / mL. The mixed solution is then coated onto a tin dioxide electron transport layer, and then annealed at 100°C for 10 min to obtain the 2,4,6-tris(4-aminophenyl)-1,3,5-triazine organic interface layer.

[0095] Comparative Example 1

[0096] Same as Example 1, except that the material of the organic interface layer is isophthalic acid.

[0097] Comparative Example 2

[0098] Same as Example 2, except that the material of the organic interface layer is 4,4-dicarboxylic acid triphenylamine.

[0099] Comparative Example 3

[0100] Same as Example 4, except that the material of the organic interface layer is 4,4-(6-phenyl-1,3,5-triazine)dibenzoic acid.

[0101] Comparative Example 4

[0102] Same as Example 5, except that the material of the organic interface layer is 4,4-(6-phenyl-1,3,5-triazine)diphenylamine.

[0103] Comparative Example 5

[0104] A pin perovskite solar cell is identical to that in Example 1, except that: no organic interface layer is provided between the NiMgLiO hole transport layer and the perovskite active layer; and the perovskite active layer is directly prepared on the NiMgLiO hole transport layer during the preparation process.

[0105] Comparative Example 6

[0106] Same as Example 6, except that the material of the organic interface layer is isophthalic acid.

[0107] Comparative Example 7

[0108] Same as Example 7, except that the material of the organic interface layer is 4,4-dicarboxylic acid triphenylamine.

[0109] Comparative Example 8

[0110] Same as Example 9, except that the material of the organic interface layer is 4,4-(6-phenyl-1,3,5-triazine)dibenzoic acid.

[0111] Comparative Example 9

[0112] Same as Example 10, except that the material of the organic interface layer is 4,4-(6-phenyl-1,3,5-triazine)diphenylamine.

[0113] Comparative Example 10

[0114] A nip perovskite solar cell is the same as in Example 6, except that: no organic interface layer is provided between the tin dioxide electron transport layer and the perovskite active layer; the perovskite active layer is prepared directly on the tin dioxide electron transport layer during the preparation process.

[0115] I. Structural Characterization:

[0116] The cross-sections of the PIN perovskite solar cell in Example 1 and the NIP perovskite solar cell in Example 6 were characterized by SEM, and the results are as follows: Figure 3-4 As shown, by Figure 3 , Figure 4 It is known that the organic interface layer can form a dense interlayer structure between the inorganic p-type semiconductor hole transport layer and the perovskite active layer, and between the inorganic n-type semiconductor electron transport layer and the perovskite active layer. The dense interlayer structure is crucial for obtaining high-efficiency and high-stability perovskite solar cells.

[0117] II. Performance Testing

[0118] (1) The performance of the PIN perovskite solar cells prepared in Examples 1-5 and Comparative Example 5, as well as the performance of the NIP perovskite solar cells prepared in Examples 6-10 and Comparative Example 10, were tested respectively (test conditions: AM1.5G, 100mW / cm²). -2 The effective area is 0.09cm². -2 ), to obtain as Figure 5 The current density versus voltage (JV) characteristic curves of the perovskite solar cell shown are derived from... Figure 5 As can be seen from a in the figure, under the same test conditions, compared with the device in Comparative Example 5, the open-circuit voltage V of the pin perovskite solar cells corresponding to Examples 1-5 modified with organic interface materials (interface modification molecules with Δ-type tri-anchored structure) is significantly higher. OC and short-circuit current density J SC All have been improved; by Figure 5 As can be seen from b in the figure, compared with the device in Comparative Example 10, the open-circuit voltage V of the nip perovskite solar cells corresponding to Examples 6-10 modified with organic interface materials is higher. OC Short-circuit current density J SC All have been improved.

[0119] Specifically, the performance results of the perovskite solar cells prepared in Examples 1-10 and Comparative Examples 1-11 are shown in Table 1. Compared with perovskite solar cells without organic interface layer modification (e.g., Comparative Example 5) and perovskite solar cells modified with organic interface materials with a dual-anchor structure (e.g., Comparative Example 1), the perovskite solar cells modified with organic interface materials based on the Δ-type triple-anchor structure of the present invention (e.g., Example 1) showed a significant improvement in cell efficiency. Among them, the perovskite solar cell modified with 4,4,4-tricarboxylic acid triphenylamine had the highest efficiency, with the pin-type perovskite solar cell reaching 22.9% and the nip-type reaching 23.7%. The interface modification molecules based on the Δ-type triple-anchor structure of the present invention are more conducive to passivating the interface defects between the semiconductor hole transport layer and the perovskite active layer, accelerating the charge extraction efficiency, thereby reducing non-radiative recombination and improving cell efficiency.

[0120] Table 1. Photovoltaic performance parameters of pin perovskite solar cells

[0121]

[0122]

[0123] (2) Contact Angle Test

[0124] The contact angles of the inorganic charge transport layers modified with organic interface materials in Examples 1-5 with the perovskite solution, and the contact angle of the unmodified inorganic charge transport layer in Comparative Example 5 with the perovskite precursor solution were tested. The results are as follows: Figure 6 As shown, we can see that the perovskite precursor solution can spread well on all six substrates. The perovskite precursor solution has good wettability in both the inorganic charge transport layer modified with organic interface material and the unmodified inorganic charge transport layer in Examples 1-5. The charge transport layer modified with organic interface material has good interfacial interaction with the perovskite solution.

[0125] (3) Steady-state fluorescence (PL) and time-resolved photoluminescence (TRPL) tests

[0126] A NiMgLiO layer, an organic interface layer (materials being 1,3,5-benzenetricarboxylic acid, triphenylamine 4,4,4-tricarboxylic acid, 1,3,5-tris(4-aminophenyl)benzene, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, respectively), and a perovskite active layer (Cs) were sequentially deposited on a transparent conductive oxide substrate FTO glass. 0.15 FA 0.85 )Pb(I 0.95 Br 0.05 3. The perovskite films were labeled as follows: 1,3,5-benzenetricarboxylic acid interface-modified perovskite film (experimental group 1), 4,4,4-triphenylamine tricarboxylic acid interface-modified perovskite film (experimental group 2), 1,3,5-tris(4-aminophenyl)benzene interface-modified perovskite film (experimental group 3), 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine interface-modified perovskite film (experimental group 4), and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine interface-modified perovskite film (experimental group 4). The membrane (experimental group 5) and control group 1 were respectively prepared by sequentially depositing a NiMgLiO layer and a perovskite active layer on a transparent conductive oxide substrate FTO glass, labeled as the original perovskite membrane. Control group 2 was prepared by sequentially depositing a NiMgLiO layer, isophthalic acid, and a perovskite active layer on a transparent conductive oxide substrate FTO glass, labeled as the isophthalic acid interface-modified perovskite membrane. Steady-state fluorescence (PL) and time-resolved photoluminescence (TRPL) tests were then performed on each sample. The results are as follows: Figure 7 and Figure 8 Show. Depend on Figure 7 It can be seen that the steady-state PL intensity of experimental groups 1-5 is significantly lower than that of the original perovskite film in control group 1 and the isophthalic acid interface-modified titanium dioxide film in control group 2. This indicates that the above-mentioned Δ-type three-anchor structure organic interface material effectively suppresses nonradiative recombination caused by nickel oxide / perovskite interface defects and accelerates carrier extraction speed. This result is confirmed in the transient PL results, such as... Figure 8As shown, we use a double exponential decay function to fit the transient PL results. Based on the following formula:

[0127] y=A1 exp(-t / τ1)+A2 exp(-t / τ2)+y0

[0128] Here, τ1 and τ2 are the lifetimes of fast decay and slow decay, respectively, and the average carrier lifetime (τ) is the mean carrier lifetime. ave The following formula is used to obtain:

[0129]

[0130] Specifically, the relevant fitting results are detailed in Table 2. Compared with the original perovskite film and the isophthalic acid interface-modified perovskite film, the average carrier lifetime of the perovskite film modified with the Δ-type tri-anchor structure organic interface material is significantly reduced. The transient PL results show that after modification with the Δ-type tri-anchor structure organic interface molecule, the defects at the nickel oxide / perovskite interface are reduced and the hole extraction rate is accelerated.

[0131] Table 2. Fitting parameters for transient fluorescence spectra of perovskite films

[0132]

[0133] (4) Battery stability test

[0134] The thermal stability of the perovskite solar cells prepared in Examples 1-5, Comparative Example 1, and Comparative Example 5 was tested. The specific testing method was as follows: the corresponding perovskite solar cells were placed on an 85°C hot table in a glove box, and their efficiency was tested at regular intervals. The results are as follows: Figure 9 As shown, within 1000 hours, the efficiency of the device in Comparative Example 5 had decreased to 51% of its initial efficiency, the efficiency of the device in Comparative Example 1 had decreased to below 60% of its initial efficiency, the efficiency of the device in Example 1 remained at 89% of its initial efficiency, the efficiency of the device in Example 2 remained at 97% of its initial efficiency, the efficiency of the device in Example 3 remained at 68% of its initial efficiency, the efficiency of the device in Example 4 remained at 92% of its initial efficiency, and the efficiency of the device in Example 5 remained at 77% of its initial efficiency. The results indicate that the thermal stability of the perovskite solar cell modified with Δ-type tri-anchored organic interface molecules is significantly improved.

[0135] Although embodiments of the present invention have been described in detail above, those skilled in the art will understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for improving the efficiency and stability of perovskite solar cells, characterized in that, An organic interface layer is first formed on the charge transport layer, and then a perovskite active layer is formed on the organic interface layer. The charge transport layer is an inorganic p-type semiconductor hole transport layer or an inorganic n-type semiconductor electron transport layer, and the organic interface material in the organic interface layer is selected from one of the following structures:

2. The method for improving the efficiency and stability of perovskite solar cells according to claim 1, characterized in that, The step of preparing the organic interface layer includes: The organic interface material is dissolved in ethanol, isopropanol or N,N-dimethylformamide to obtain an organic interface material solution with a concentration of 0.1-10 mg / mL. The organic interface material solution is then coated onto the charge transport layer by spin coating, blade coating, spraying, slot coating or immersion. Finally, the layer is annealed at an annealing temperature of 70-150°C for 5-60 minutes.

3. A perovskite solar cell, characterized in that, The perovskite solar cell is a pin-type perovskite solar cell, which includes: a transparent conductive oxide substrate (1), an inorganic p-type semiconductor hole transport layer (21), a perovskite active layer (4), and an organic interface layer (3) disposed between the inorganic p-type semiconductor hole transport layer (21) and the perovskite active layer (4). Alternatively, the perovskite solar cell is a nip-type perovskite solar cell, which includes: a transparent conductive oxide substrate (1), an inorganic n-type semiconductor electron transport layer (22), a perovskite active layer (4), and an organic interface layer (3) disposed between the inorganic n-type semiconductor electron transport layer (22) and the perovskite active layer (4). The material of the organic interface layer is selected from one of the following structures:

4. The perovskite solar cell according to claim 3, characterized in that, The perovskite solar cell with a pin-type structure includes, from bottom to top, a transparent conductive oxide substrate (1), an inorganic p-type semiconductor hole transport layer (21), an organic interface layer (3), a perovskite active layer (4), an electron transport layer (51), a hole blocking layer (7), and an electrode layer (6). The nip-type perovskite solar cell includes, from bottom to top, a transparent conductive oxide substrate (1), an inorganic n-type semiconductor electron transport layer (22), an organic interface layer (3), a perovskite active layer (4), a hole transport layer (52), and an electrode layer (6).

5. The perovskite solar cell according to claim 3, characterized in that, The inorganic p-type semiconductor hole transport layer material is selected from one of nickel oxide, doped nickel oxide, cuprous thiocyanate, or cuprous chromate.

6. The perovskite solar cell according to claim 3, characterized in that, The inorganic n-type semiconductor electron transport layer material is selected from either tin dioxide or titanium dioxide.

7. The perovskite solar cell according to claim 3, characterized in that, The perovskite active layer material has an ABX3 structure, wherein A is selected from methylammonium, formamidinium, and Cs. + One or more of them, B is selected from Pb 2+ Sn 2+ One or two of them, X is selected from I - ,Br - Cl - One or more of them.

8. The perovskite solar cell according to claim 4, characterized in that, The electron transport layer material is selected from isomethyl [6,6]-phenyl-C71-butyrate, C 60 Or C 60 One of the derivatives.

9. The perovskite solar cell according to claim 4, characterized in that, The hole transport layer material is selected from 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene or cuprous thiocyanate.

10. The perovskite solar cell according to claim 4, characterized in that, The electrode layer can be a single-layer structure or a double-layer structure. The material of the single-layer structure is selected from silver, gold, copper, chromium, indium tin oxide, aluminum-doped zinc oxide, or tungsten-doped indium oxide. The double-layer structure is selected from bismuth-copper double-layer structure, bismuth-gold double-layer structure, bismuth-silver double-layer structure, chromium-copper double-layer structure, chromium-gold double-layer structure, or chromium-silver double-layer structure.

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