Perovskite body phase passivation method and application

Abstract

The invention discloses a perovskite bulk phase passivation method and application, and relates to the technical field of preparation of perovskite photoelectric devices, functional organic molecules are added into an aprotic polar solvent to prepare a passivator mother solution, the passivator mother solution is added into a perovskite precursor solution according to a certain concentration, and the perovskite bulk phase passivation method is used for preparing a perovskite thin film. Therefore, optimized nucleation crystallization of the perovskite thin film and in-situ passivation of a thin film coherent interface are realized. By optimizing the nucleation crystallization process, the quality of the perovskite film is improved, the interface defect of the film is effectively improved, and the efficiency and the stability of a photoelectric device are further improved. The method is suitable for preparation of organic and inorganic perovskite material systems and photoelectric devices thereof.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of perovskite optoelectronic devices, and particularly relates to a method for bulk passivation of perovskite and its application. Background Art

[0002] In recent years, organic-inorganic halide perovskite materials have shown great application potential in solar cell applications. Currently, the power conversion efficiency (PCE) of halide perovskite solar cells (PSCs) has been increased to a certified efficiency of 26.7%, which is comparable to that of traditional crystalline silicon solar cells. This is mainly due to the excellent optoelectronic properties of perovskite materials, including a high optical absorption coefficient (10 5 cm -1 ), a long carrier diffusion length (>1 μm), an adjustable direct bandgap, etc.

[0003] Perovskite materials have attracted much attention in the fields of solar cells, light-emitting diodes, and photodetectors due to their excellent optoelectronic properties. However, defects in perovskite materials significantly affect their performance and stability. Defects are mainly divided into bulk defects and surface / interface defects, which act as non-radiative recombination centers, reducing the carrier lifetime and possibly causing material degradation. Therefore, understanding the types, formation mechanisms, and effects of perovskite defects is crucial for optimizing device performance. Among them, the device performance of perovskite solar cells is more sensitive to bulk defects. Bulk defects mainly exist inside the lattice of perovskite materials, affecting the processes of carrier generation, transport, and recombination, and thus affecting the optoelectronic conversion efficiency and stability of the device.

[0004] In recent years, due to the advantages of simple process, low cost, stable effect, and easy amplification in bulk passivation, it has gradually become one of the research hotspots in perovskite defect passivation. So far, many passivation methods have been proposed to reduce the defect density and defect-induced recombination. Additives based on Lewis acid-base theory, including solvents, ionic liquids, small molecules, and polymers, are used to modify perovskite films with various functional groups.

[0005] Small molecule bulk passivation shows significant advantages in the repair of bulk defects in perovskite solar cells due to its high reactivity, strong permeability, process compatibility, and versatility. Compared with other passivation methods, small molecule passivation has unique potential in improving device performance and reducing costs. Future research should focus on developing more stable and efficient small molecule passivators and optimizing the passivation process to promote the commercial application of perovskite solar cells.

[0006] However, despite the significant advantages of small-molecule bulk passivation, some common problems still exist:

[0007] 1. Interference with the perovskite crystallization process: It competes with perovskite crystallization, leading to a decline in film quality. When the compatibility between small molecules and perovskite materials is poor, phase separation may occur, forming impurity phases.

[0008] 2. Long-term stability: Some small molecules may degrade under light or humidity conditions, and more stable passivators need to be developed.

[0009] 3. Process optimization: The introduction method and concentration of small molecules need to be further optimized to achieve the best passivation effect. Summary of the Invention

[0010] In view of the deficiencies in the prior art, the present invention provides a method for perovskite bulk passivation and its application in solar cells.

[0011] To achieve the above objectives, the technical solution of the present invention is as follows:

[0012] A method for perovskite bulk passivation, which includes the following steps:

[0013] S1: Dissolve a functional organic molecule in an aprotic polar solvent to prepare a passivator mother liquor; the functional organic molecule is an aromatic compound composed of Lewis acid functional groups and Lewis base functional groups with a certain spatial position distribution, wherein the Lewis acid functional group and the Lewis base functional group are isolated by one or more aromatic rings and appear in a non-ortho position form;

[0014] S2: Add the passivator mother liquor obtained in S1 to the perovskite precursor solution to obtain a perovskite precursor solution mixture;

[0015] S3: Use the perovskite precursor solution mixture obtained in S2, adopt a wet preparation process, and form a passivated perovskite film through coating, desolvation, and post-annealing.

[0016] This method can realize the regulation of the wet nucleation and crystallization process of perovskite and the in-situ passivation of the film interface. This method is applicable to passivate various perovskite systems in perovskite solar cells and their optoelectronic devices.

[0017] Optionally, the Lewis acid functional group includes at least one of a boric acid group (-B(OH)2), a phosphoric acid group (-PO(OH)2), and a fluorine-containing group (-F, -CF3); the Lewis base functional group includes at least one of a carbonyl group (-C=O), an ether group (-O-), an ester group (-R-O-O-R-), amines (-NH2, -NR2), a phosphoryl group (-P=O), pyridine, and its derivatives.

[0018] Optionally, the functional organic molecule is at least one of diethyl (trifluoromethylphenyl) phosphate, ethyl bis(p-trifluoromethylphenyl) phosphate, and diethyl (p-aminophenyl) phosphate.

[0019] Optionally, the aprotic polar solvent includes at least one of acetonitrile, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and N-ethylpyrrolidone (NEP).

[0020] Optionally, the concentration of the functional organic molecule in the perovskite precursor liquid mixture is 0.8 - 1.2 mg / mL.

[0021] Optionally, in step S3, the perovskite film is formed on the hole transport layer or the electron transport layer of the perovskite solar cell, or on the hole transport layer or the electron transport layer with a passivated surface; wherein the passivation layer is formed from the passivating agent mother liquor.

[0022] Optionally, the perovskite precursor liquid is used to prepare at least one of the following types of ABX3 perovskite films:

[0023] i. Organic-inorganic perovskite film, wherein the A-site cation includes at least one of formamidinium (FA + ), methylammonium (MA + ), or at least one of cesium (Cs + ), rubidium (Rb + ), the B-site ion includes Pb 2+ , Sn 4+ , and the X-site ion includes one or more of I - , Cl - , Br - ;

[0024] ii. Pure inorganic perovskite film, wherein the A-site cation is Cs + , the B-site ion includes at least one of Pb 2+ , Sn 4+ , and the X-site ion includes one or more of I-, Cl-, Br-.

[0025] Optionally, the thickness of the perovskite film is 100 - 500 nm.

[0026] Optionally, the coating method includes any one of the following:

[0027] i. Dynamic spin coating, with a rotation speed of 5000 - 6000 rpm;

[0028] ii. Static spin coating, with a rotation speed of 1000 - 3000 rpm;

[0029] iii. Knife coating, with an initial speed of 1.0 - 2.0 mm / s and an acceleration of 0.01 - 0.05 mm 2 / s;

[0030] iv. Slot die coating, with a distance between the coating head and the substrate of 200 - 300 μm and a printing speed of 3 - 10 mm / s.

[0031] Optionally, the desolvation method includes at least one of vacuum treatment, anti-solvent treatment, gas-assisted blowing, photo-assisted treatment, or chemical treatment.

[0032] Optionally, the post-annealing method is thermal annealing or infrared-assisted annealing, where: the temperature range of the thermal annealing is 100 - 150 °C and the post-annealing time is 10 - 60 min; for the infrared-assisted annealing, the wet film after desolvation is placed in the chamber of an infrared-assisted annealing device, the chamber temperature rises to 300 - 350 °C within 35 s, and then it is naturally cooled to 20 - 30 °C.

[0033] A perovskite solar cell, which includes a bottom electrode, a hole transport layer (HTL), a perovskite active layer, an electron transport layer (ETL), and a top electrode, and the perovskite active layer is formed by the perovskite bulk passivation method as described above.

[0034] The perovskite solar cell includes an organic-inorganic perovskite solar cell or an inorganic perovskite solar cell.

[0035] Among the functional organic molecules:

[0036] The Lewis acid functional group has an electron acceptor function, can form hydrogen bonds with A-site cations, X-site halogen ions, etc. in the perovskite precursor solution, reduce the solubility of the precursor, accelerate the nucleation rate, form more uniform nucleation sites, and enrich at the grain boundaries and the upper surface of the perovskite film after film formation to passivate related basic defects;

[0037] The Lewis base functional group has the ability of a lone pair electron donor, can form chemical bonds with Pb 2+ in the precursor solution and metal ions in the inorganic transport layer (such as Ni 2+ , Sn 4+ ); through the "organic molecule - Pb 2+ " chemical anchoring effect, the nucleation and crystallization process mediated by [PbI6] 4- octahedrons in the perovskite wet film is regulated, and at the same time, the interaction of "organic molecule - Ni 2+ " or "organic molecule - Sn 4+ " promotes the spontaneous deposition of organic small molecules at the inorganic transport layer / perovskite interface during the preparation of the perovskite film to achieve in-situ interface modification and passivation;

[0038] The Lewis acid and the basic functional group can synergistically play a role in defect passivation and interface stability enhancement:

[0039] 1. The Lewis basic functional group reduces non-radiative recombination by passivating surface defects, and the Lewis acidic functional group forms a low-dimensional perovskite structure to optimize the interfacial energy level alignment. The two together improve the open-circuit voltage (VOC) and fill factor (FF) of the device.

[0040] 2. The hydroxyl group of the Lewis basic functional group can enhance interfacial contact with the Lewis acidic functional group on the perovskite surface through hydrogen bonding or electrostatic interaction, form a more stable interface, and promote charge transport and extraction.

[0041] 3. The Lewis basic functional group and the acidic functional group can enhance the contact between interfaces, promote charge transport, and solve the problem of discontinuity of the electron transport layer caused by the hydrophobic interface.

[0042] Since the Lewis acid and base functional groups will form different coordinations or chemical bonds, and the bonding or coordination ability of these functional groups is affected by their positions, that is, the position and number of condensed or aromatic rings; therefore, the Lewis acidic functional group and the Lewis basic functional group need to be isolated by a single or multiple aromatic rings to avoid adverse internal reactions between molecules; if there is only one aromatic ring in the molecule, the Lewis acid and base groups are located at the meta and para positions of the aromatic ring; if the molecule contains condensed and aromatic rings (such as naphthalene, carbazole, carbazole indole, phenanthrene, etc.), the Lewis acid and base groups cannot appear in the ortho form in terms of spatial position.

[0043] The beneficial effects of the present invention are as follows:

[0044] 1. The functional organic molecule used in the present invention optimizes the nucleation and crystallization process, improves the quality of the perovskite thin film, and effectively improves the interfacial defects of the thin film, thereby enhancing the efficiency and stability of the optoelectronic device.

[0045] 2. The functional organic molecule used in the present invention is a bulk phase additive applicable to perovskites in multiple systems, and is applicable to organic and inorganic perovskite systems.

[0046] Other features and beneficial effects of the present invention will be described in the subsequent specification, and part of them will be obvious from the specification or understood by implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention will be further described below with reference to the drawings and embodiments.

[0048] Figure 1 It is the crystallization intermediate phase diagram of the perovskite bulk phase of Comparative Example 2;

[0049] Figure 2 It is the crystallization intermediate phase diagram of adding TFPEA to the perovskite bulk phase of Example 4;

[0050] Figure 3 Crystallization intermediate phase diagram of adding EBTP to the perovskite body phase in Example 5;

[0051] Figure 4 Scanning electron microscope images of Comparative Example 2, Example 4, and Example 11;

[0052] Figure 5 In-situ PL spectrum of the crystallization of the perovskite body phase in Comparative Example 2;

[0053] Figure 6 In-situ PL spectrum of the crystallization of adding TFPEA to the perovskite body phase in Example 1;

[0054] Figure 7 On the left is the contact angle diagram of the perovskite body phase in Comparative Example 2, and on the right is the contact angle diagram of adding TFPEA to the perovskite body phase in Example 2. Detailed implementation manners

[0055] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments.

[0056] The structural formula of the functional organic molecule used in the embodiment is as follows:

[0057] The structural formula of diethyl (4-trifluoromethylphenyl) phosphate (TFPEA) is:

[0058] The structural formula of bis(4-trifluoromethylphenyl) ethyl phosphate (EBTP) is:

[0059] The structural formula of diethyl (4-aminophenyl) phosphate (PPE) is:

[0060] The basic structure and preparation process of the perovskite solar cells in the following examples and comparative examples are as follows:

[0061] (1) Pretreatment of the cell substrate:

[0062] Substrate pretreatment: Place the etched FTO transparent conductive glass on the cleaning rack, and ultrasonically clean it successively with an aqueous solution of sodium dodecyl sulfate (or other surfactants), isopropanol, and ethanol, with each cleaning time being 15 minutes. After cleaning, take it out and dry it with nitrogen, and then put it into a plasma cleaner to clean the glass surface for 15 minutes. It also serves as the bottom electrode at the same time.

[0063] (2) Preparation of the hole transport layer is carried out by the following preparation method:

[0064] 1) Inverted NiO xHole transport layer: Dissolve 32.11 mg of nickel acetylacetonate in 1 mL of anhydrous ethanol, then add 17 μL of concentrated hydrochloric acid thereto, and ultrasonicate for 15 min. Filter before use. Subsequently, spin-coat this solution statically on a clean FTO substrate at a speed of 4000 rpm for 20 s. After the spin-coating is completed, pre-anneal the substrate at 180 °C for 10 min, and then transfer the substrate to a hot plate at 400 °C for annealing for 45 min. Take it out after the temperature drops below 100 °C.

[0065] 2) Normal Spiro-OMeTAD hole transport layer: Dissolve 90 mg of Spiro-OMeTAD in 1 mL of chlorobenzene and shake for 20 min. Subsequently, spin-coat this solution dynamically on the perovskite film at a speed of 4000 rpm for 30 s.

[0066] (3) Preparation of the perovskite active layer. The preparation methods of the precursor solutions of different perovskite systems are as follows:

[0067] 1) Formamidinium cesium system FA 0.9 Cs 0.1 PbI3: Dissolve lead iodide, cesium iodide, and formamidinium iodide in a mixed solution of N,N-dimethylformamide and N-methylpyrrolidone, and shake in a nitrogen glove box for 3 h. Add an appropriate amount of methylammonium chloride 5 min before the end of shaking. Filter before use. Among them, the feeding ratios of lead iodide, cesium iodide, formamidinium iodide, N,N-dimethylformamide, N-methylpyrrolidone, and methylammonium chloride are 311 mg: 13 mg: 113.4 mg: 586 μL: 96 μL: 20 mg.

[0068] 2) Ternary system (FA 0.83 MA 0.17 ) 0.95 Cs 0.05 Pb(I 0.9 Br 0.1 )3: Dissolve lead iodide, formamidinium iodide, methylammonium iodide, and cesium iodide in a mixed solution of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone, and stir overnight in a nitrogen glove box or heat and stir at 60 °C for 1 h. Filter before use. Among them, the feeding ratios of lead iodide, formamidinium iodide, methylammonium iodide, cesium iodide, N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone are 509.4 mg: 176.6 mg: 33.1 mg: 16.9 mg: 800 μL: 180 μL: 20 μL.

[0069] 3) Multicomponent system Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05)3: Dissolve rubidium iodide, cesium iodide, methylammonium bromide, formamidinium iodide, lead iodide, and lead bromide in a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide, shake in a nitrogen glove box for 3 - 5 h, and filter before use. The feeding ratio of rubidium iodide, cesium iodide, methylammonium bromide, formamidinium iodide, lead iodide, and lead bromide dissolved in N,N-dimethylformamide and dimethyl sulfoxide is: 15.9 mg: 19.5 mg: 8.4 mg: 219.5 mg: 656.9 mg: 21.7 mg: 800 μL: 200 μL.

[0070] (4) Preparation of the electron transport layer:

[0071] 1) Inverted PC 61 BM electron transport layer: Take 20 mg / mL PC 61 BM powder and dissolve it in 1 mL of chlorobenzene, shake for 20 min; then spin-coat this solution dynamically on the perovskite film at a speed of 2000 rpm for 30 s.

[0072] 2) Preparation of the normal SnO2 electron transport layer: Take 30 mg of SnO2 nanoparticles and dissolve them in 1 mL of isopropyl alcohol, shake to dissolve, filter before use, and then spin-coat this solution statically on a clean FTO substrate at a speed of 2000 rpm for 60 s. After the spin-coating is completed, anneal the substrate on a hot plate at 200 °C for 20 min, and take it out after the temperature drops below 80 °C.

[0073] (5) Preparation of the hole-blocking layer:

[0074] Take 0.5 mg of BCP powder and dissolve it in 1 mL of isopropyl alcohol, shake until the powder is completely dissolved, filter before use; then spin-coat this solution dynamically on PC 61 BM at a speed of 4000 rpm for 20 s; then, post-anneal on a hot plate at 100 °C for 3 - 4 min.

[0075] (6) Preparation of the metal electrode:

[0076] Evaporate a 100-nm-thick metal silver electrode using a vacuum thermal evaporation coater to obtain a perovskite solar cell device. The effective area of the metal electrode is 0.12 cm 2 .

[0077] Example 1

[0078] The perovskite bulk passivation method of Example 1 includes the following steps:

[0079] S1: Weigh 1 μL of diethyl (p-trifluoromethylphenyl) phosphate (TFPEA) (this small molecule is in liquid state with a concentration of 20 mg / mL) and dissolve it in 60 μL of N,N-dimethylformamide. Take 50 μL and add it to 950 μL of the perovskite precursor solution to form a perovskite precursor solution mixture containing 1.0 mg / mL of TFPEA, and shake for 5 - 10 min; the perovskite system is the formamidinium cesium system (FA 0.9 Cs 0.1 PbI3)

[0080] S2: Dynamically spin-coat the perovskite precursor solution mixture prepared in S1 at a speed of 6000 rpm for 35 s, and drop the antisolvent ethyl acetate at the 5th second from the end to deposit the perovskite thin film on the SnO2 electron transport layer;

[0081] S3: Anneal the perovskite thin film prepared in S2 at 110 °C for 60 min to obtain a passivated perovskite thin film as the perovskite active layer of the solar cell.

[0082] The solar cell of this example adopts the structure of FTO substrate / SnO2 electron transport layer / perovskite active layer / Spiro-OMeTAD hole transport layer / top metal electrode.

[0083] In this example, TFPEA, as a functional organic molecule, is hardly volatile and contains trifluoromethyl and organic phosphate groups. It induces crystallization in the perovskite and does not compete with crystallization. At the same time, it can be stabilized at the upper and lower interfaces of the perovskite after the perovskite film is formed to eliminate the influence of excess lead iodide on the perovskite thin film and enhance the humidity resistance of the perovskite thin film.

[0084] Example 2

[0085] The method for bulk passivation of the perovskite in Example 2 includes the following steps:

[0086] S1: Weigh 1 μL of bis(p-trifluoromethylphenyl) phosphate (EBTP) (this small molecule is in liquid state with a concentration of 20 mg / mL) and dissolve it in 60 μL of N,N-dimethylformamide. Take 50 μL and add it to 950 μL of the perovskite precursor solution to form a perovskite precursor solution mixture containing 1.0 mg / mL of EBTP, and shake for 5 - 10 min; the perovskite system is the formamidinium cesium system (FA 0.9 Cs 0.1 PbI3);

[0087] S2: Dynamically spin-coat the perovskite precursor solution mixture prepared in S1 at a speed of 6000 rpm for 35 s, and drop the antisolvent ethyl acetate at the 5th second from the end to deposit the perovskite thin film on the SnO2 electron transport layer;

[0088] S3: Anneal the perovskite film prepared in S2 at 110 °C for 60 min to obtain a passivated perovskite film, which serves as the perovskite active layer of the solar cell.

[0089] The solar cell of this example adopts the structure of FTO substrate / SnO2 electron transport layer / perovskite active layer / Spiro-OMeTAD hole transport layer / top metal electrode.

[0090] Example 3

[0091] The method for bulk passivation of perovskite in Example 3 includes the following steps:

[0092] S1: Weigh 1 μL of diethyl (4-aminophenyl) phosphate (PPE) (this small molecule is in liquid state with a concentration of 20 mg / mL), dissolve it in 60 μL of N,N-dimethylformamide, take 50 μL and add it to 950 μL of perovskite precursor solution to form a perovskite precursor solution mixture containing 1.0 mg / mL of PPE, and shake it for 5 - 10 min; the perovskite system is formamidinium cesium system (FA 0.9 Cs 0.1 PbI3);

[0093] S2: Dynamically spin-coat the perovskite precursor solution mixture prepared in S1 at a speed of 6000 rpm for 35 s, and drop the antisolvent ethyl acetate at the 5th second from the end to deposit the perovskite film on the SnO2 electron transport layer;

[0094] S3: Anneal the perovskite film prepared in S2 at 110 °C for 60 min to obtain a passivated perovskite film, which serves as the perovskite active layer of the solar cell.

[0095] The solar cell of this example adopts the structure of FTO substrate / SnO2 electron transport layer / perovskite active layer / Spiro-OMeTAD hole transport layer / top metal electrode.

[0096] Example 4

[0097] The method for bulk passivation of perovskite in Example 4 includes the following steps:

[0098] S1: Weigh 1 μL of diethyl (4-(trifluoromethyl)phenyl) phosphate (TFPEA) (this small molecule is in liquid state with a concentration of 20 mg / mL), dissolve it in 60 μL of N,N-dimethylformamide, take 50 μL and add it to 950 μL of perovskite precursor solution to form a perovskite precursor solution mixture containing 1.0 mg / mL of TFPEA, and shake it for 5 - 10 min; the perovskite precursor is a multi-component system of Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I0.95 Br 0.05 )3;

[0099] S2: Spin-coat the perovskite precursor liquid mixture prepared in S1 statically at 1000 rpm for 10 s, then accelerate to 3000 rpm at an acceleration of 2000 rpm and hold for 40 s. Drop the antisolvent chlorobenzene in the last 5 s to deposit the perovskite thin film onto the NiO x hole transport layer;

[0100] S3: Anneal the perovskite thin film prepared in S2 at 100 °C for 30 min to obtain a passivated perovskite thin film as the perovskite active layer of the solar cell.

[0101] The solar cell of this example uses an FTO substrate / NiO x hole transport layer / perovskite active layer / PC 61 BM electron transport layer / top metal electrode structure.

[0102] Example 5

[0103] The perovskite bulk passivation method of Example 5 includes the following steps:

[0104] S1: Weigh 1 μL of bis(4-(trifluoromethyl)phenyl) phosphate (EBTP) (this small molecule is liquid, with a concentration of 20 mg / mL) and dissolve it in 60 μL of N,N-dimethylformamide. Take 50 μL and add it to 950 μL of the perovskite precursor solution to form a perovskite precursor liquid mixture containing 1.0 mg / mL of EBTP, and shake for 5 - 10 min; the perovskite precursor is a multi-component system of Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05 )3;

[0105] S2: Spin-coat the perovskite precursor liquid mixture prepared in S1 statically at 1000 rpm for 10 s, then accelerate to 3000 rpm at an acceleration of 2000 rpm and hold for 40 s. Drop the antisolvent chlorobenzene in the last 5 s to deposit the perovskite thin film onto the NiO x hole transport layer;

[0106] S3: Anneal the perovskite thin film prepared in S2 at 100 °C for 30 min to obtain a passivated perovskite thin film as the perovskite active layer of the solar cell.

[0107] The solar cell of this example uses an FTO substrate / NiO x hole transport layer / perovskite active layer / PC 61Structure of the BM electron transport layer / top metal electrode.

[0108] Example 6

[0109] The perovskite bulk passivation method of Example 6 includes the following steps:

[0110] S1: Weigh 1 μL of diethyl (4-aminophenyl) phosphate (PPE) (this small molecule is liquid, with a concentration of 20 mg / mL), dissolve it in 60 μL of N,N-dimethylformamide, take 50 μL and add it to 950 μL of the perovskite precursor solution to form a perovskite precursor solution mixture containing 1.2 mg / mL of PPE, and shake for 5 - 10 min; the perovskite precursor is a multi-component system of Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05 )3;

[0111] S2: Spin-coat the perovskite precursor solution mixture prepared in S1 statically at 1000 rpm for 10 s, then accelerate to 3000 rpm at an acceleration of 2000 rpm and hold for 40 s. Drop the antisolvent chlorobenzene in the last 5 s, and deposit the perovskite film on the NiO x hole transport layer;

[0112] S3: Anneal the perovskite film prepared in S2 at 100 °C for 30 min to obtain a passivated perovskite film, which is used as the perovskite active layer of the solar cell.

[0113] The solar cell of this example uses the structure of FTO substrate / NiO x hole transport layer / perovskite active layer / PC 61 BM electron transport layer / top metal electrode.

[0114] Example 7

[0115] The perovskite bulk passivation method of Example 7 includes the following steps:

[0116] S1: Weigh 1 μL of diethyl (4-(trifluoromethyl)phenyl) phosphate (TFPEA) (this small molecule is liquid, with a concentration of 20 mg / mL), dissolve it in 60 μL of N,N-dimethylformamide, take 50 μL and add it to 950 μL of the perovskite precursor solution to form a perovskite precursor solution mixture containing 1.0 mg / mL of TFPEA, and shake for 5 - 10 min; the perovskite precursor is a ternary system (FA 0.83 MA 0.17 ) 0.95 Cs 0.05 Pb(I 0.9 Br0.1 ) 3;

[0117] S2: Spin-coat the perovskite precursor liquid mixture prepared in S1 statically at 1300 rpm for 5 s, then accelerate it to 5000 rpm at an acceleration of 2000 rpm and hold for 40 s. Drop the antisolvent anisole at the 5th second from the end, and deposit the perovskite thin film onto the NiO x hole transport layer;

[0118] S3: Anneal the perovskite thin film prepared in S2 at 100 °C for 30 min to obtain a passivated perovskite thin film as the perovskite active layer of the solar cell.

[0119] The solar cell of this example adopts the structure of FTO substrate / NiO x hole transport layer / perovskite active layer / PC 61 BM electron transport layer / top metal electrode.

[0120] Example 8

[0121] The perovskite bulk passivation method of Example 8 includes the following steps:

[0122] S1: Weigh 1 μL of bis(4-trifluoromethylphenyl) phosphate (EBTP) (this small molecule is liquid, with a concentration of 20 mg / mL), dissolve it in 60 μL of N,N-dimethylformamide, take 50 μL and add it to 950 μL of perovskite precursor liquid to form a perovskite precursor liquid mixture containing 1.0 mg / mL of EBTP, and shake for 5 - 10 min; the perovskite precursor is a ternary system (FA 0.83 MA 0.17 ) 0.95 Cs 0.05 Pb(I 0.9 Br 0.1 ) 3;

[0123] S2: Spin-coat the perovskite precursor liquid mixture prepared in S1 statically at 1300 rpm for 5 s, then accelerate it to 5000 rpm at an acceleration of 2000 rpm and hold for 40 s. Drop the antisolvent anisole at the 5th second from the end, and deposit the perovskite thin film onto the NiO x hole transport layer;

[0124] S3: Anneal the perovskite thin film prepared in S2 at 100 °C for 30 min to obtain a passivated perovskite thin film as the perovskite active layer of the solar cell.

[0125] The solar cell of this example adopts the structure of FTO substrate / NiO x hole transport layer / perovskite active layer / PC 61Structure of the BM electron transport layer / top metal electrode.

[0126] Example 9

[0127] The bulk passivation method of the perovskite in Example 9 includes the following steps:

[0128] S1: Weigh 1 μL of diethyl (4-aminophenyl) phosphate (PPE) (this small molecule is liquid, with a concentration of 20 mg / mL) and dissolve it in 60 μL of N,N-dimethylformamide. Take 50 μL and add it to 950 μL of the perovskite precursor solution to form a perovskite precursor solution mixture containing 1.0 mg / mL of PPE, and shake for 5 - 10 min; the perovskite precursor is a ternary system (FA 0.83 MA 0.17 ) 0.95 Cs 0.05 Pb(I 0.9 Br 0.1 )3;

[0129] S2: Spin-coat the perovskite precursor solution mixture prepared in S1 statically at a speed of 1300 rpm for 5 s, then accelerate to 5000 rpm at an acceleration of 2000 rpm and hold for 40 s. Drop the antisolvent anisole in the last 5 s, and deposit the perovskite film on the NiO x hole transport layer;

[0130] S3: Anneal the perovskite film prepared in S2 at 100 °C for 30 min to obtain a passivated perovskite film, which is used as the perovskite active layer of the solar cell.

[0131] The solar cell in this example adopts the structure of FTO substrate / NiO x hole transport layer / perovskite active layer / PC 61 BM electron transport layer / top metal electrode.

[0132] Example 10

[0133] The bulk passivation method of the perovskite in Example 10 combined with interface modification includes the following steps:

[0134] S1: Weigh 1 μL of diethyl (4-(trifluoromethyl)phenyl) phosphate (TFPEA) (this small molecule is liquid, with a concentration of 20 mg / mL) and dissolve it in 1 mL of isopropanol to obtain a precursor solution containing the TFPEA solution, and shake for 5 - 10 min;

[0135] S2: Spin-coat the solution prepared in S1 statically on the SnO2 electron transport layer at a speed of 3000 rpm / s for 30 s, and then anneal it on a hot plate at 100 °C for 10 min to form a TFPEA passivation layer;

[0136] S3: Weigh 1 μL of diethyl (p-trifluoromethylphenyl) phosphate (TFPEA) (this small molecule is in liquid state with a concentration of 20 mg / mL), dissolve it in 60 μL of N,N-dimethylformamide, take 50 μL and add it to 950 μL of perovskite precursor solution to form a perovskite precursor solution mixture containing 1.0 mg / mL of TFPEA, and shake for 5 - 10 min; the perovskite system is the formamidinium cesium system (FA 0.9 Cs 0.1 PbI3)

[0137] S4: Spin-coat the perovskite precursor solution mixture prepared in S3 dynamically at a speed of 6000 rpm / s for 35 s, and drop the antisolvent ethyl acetate at the 5th second from the end to deposit the perovskite thin film onto the TFPEA passivation layer;

[0138] S5: Anneal the perovskite thin film prepared in S4 at 110 °C for 60 min to obtain a passivated perovskite thin film, which serves as the perovskite active layer of the solar cell.

[0139] The solar cell of this example adopts the structure of FTO substrate / SnO2 electron transport layer / TFPEA passivation layer / perovskite active layer / Spiro-OMeTAD hole transport layer / top metal electrode.

[0140] Example 11

[0141] The perovskite bulk passivation method of Example 11 combined with interface modification includes the following steps:

[0142] S1: Weigh 1 μL of diethyl (p-trifluoromethylphenyl) phosphate (TFPEA) (this small molecule is in liquid state with a concentration of 20 mg / mL), dissolve it in 1 mL of isopropanol to obtain a precursor solution containing TFPEA solution, and shake for 5 - 10 min;

[0143] S2: Spin-coat the solution prepared in S1 statically on the NiOx hole transport layer at a speed of 3000 rpm / s for 30 s, and then anneal it on a hot plate at 100 °C for 10 min to form a TFPEA passivation layer;

[0144] S3: Weigh 1 μL of diethyl (p-trifluoromethylphenyl) phosphate (TFPEA) (this small molecule is in liquid state with a concentration of 20 mg / mL), dissolve it in 60 μL of N,N-dimethylformamide, take 50 μL and add it to 950 μL of perovskite precursor solution to form a perovskite precursor solution mixture containing 1.0 mg / mL of TFPEA, and shake for 5 - 10 min; the perovskite precursor is a multi-component system of Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05)3;

[0145] S4: Spin-coat the perovskite precursor liquid mixture prepared in S3 statically at a speed of 1000 rpm / s for 10 s, then accelerate to 3000 rpm / s at an acceleration of 2000 rpm / s and hold for 40 s. Drop the antisolvent chlorobenzene in the last 5 s to deposit the perovskite thin film on the NiOx hole transport layer;

[0146] S5: Anneal the perovskite thin film prepared in S4 at 100 °C for 30 min to obtain a passivated perovskite thin film as the perovskite active layer of the solar cell.

[0147] The solar cell of this embodiment uses the structure of FTO substrate / NiOx hole transport layer / TFPEA passivation layer / perovskite active layer / PC 61 BM electron transport layer / top metal electrode.

[0148] Example 12

[0149] The perovskite bulk passivation method of Example 12 combines interface modification, including the following steps:

[0150] S1: Weigh 1 μL of diethyl (p-trifluoromethylphenyl) phosphate (TFPEA) (this small molecule is liquid, with a concentration of 20 mg / mL) and dissolve it in 1 mL of isopropanol to obtain a precursor liquid containing TFPEA solution, and shake it for 5 - 10 min;

[0151] S2: Spin-coat the solution prepared in S1 statically on the NiOx hole transport layer at a speed of 3000 rpm / s for 30 s, and then anneal it on a hot plate at 100 °C for 10 min to form a TFPEA passivation layer;

[0152] S3: Weigh 1 μL of diethyl (p-trifluoromethylphenyl) phosphate (TFPEA) (this small molecule is liquid, with a concentration of 20 mg / mL) and dissolve it in 60 μL of N,N-dimethylformamide. Take 50 μL and add it to 950 μL of perovskite precursor liquid to form a perovskite precursor liquid mixture containing 1.0 mg / mL of TFPEA, and shake it for 5 - 10 min; The perovskite precursor is a ternary system (FA 0.83 MA 0.17 ) 0.95 Cs 0.05 Pb(I 0.9 Br 0.1 )3;

[0153] S4: Spin-coat the perovskite precursor liquid mixture prepared in S3 statically at a speed of 1300 rpm / s for 5 s, then accelerate to 5000 rpm / s at an acceleration of 2000 rpm / s and hold for 40 s. Drop the antisolvent anisole in the last 5 s to deposit the perovskite thin film on the TFPEA passivation layer;

[0154] S5: The perovskite film prepared in S4 is annealed at 100 °C for 30 min to obtain a passivated perovskite film, which is used as the perovskite active layer of the solar cell.

[0155] The solar cell of this example adopts the structure of FTO substrate / NiOx hole transport layer / TFPEA passivation layer / perovskite active layer / PC 61 BM electron transport layer / top metal electrode.

[0156] Comparative Example 1

[0157] The difference between Comparative Example 1 and Example 1 is that the perovskite film is not passivated, and the formamidinium cesium-based perovskite film FA 0.9 Cs 0.1 PbI3 is directly prepared on the SnO2 electron transport layer as the active perovskite layer. The specific steps are as follows: The formamidinium cesium-based (FA 0.9 Cs 0.1 PbI3) perovskite precursor solution is dynamically spin-coated at a speed of 6000 rpm for 35 s, and the antisolvent ethyl acetate is dropped at the 5th second from the end, and then annealed at 110 °C for 60 min to form a perovskite film.

[0158] Comparative Example 2

[0159] The difference between Comparative Example 2 and Example 4 is that the perovskite film is not passivated, and the multi-component perovskite film Rb x is directly prepared on the NiO 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05 )3 is used as the active perovskite layer. The specific steps are as follows: The multi-component (Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05 )3) perovskite precursor solution is statically spin-coated at a speed of 1000 rpm for 10 s and then accelerated to 3000 rpm at an acceleration of 2000 rpm and maintained for 40 s. The antisolvent chlorobenzene is dropped at the 5th second from the end, and then annealed at 100 °C for 30 min to form a perovskite film.

[0160] Comparative Example 3

[0161] The difference between Comparative Example 3 and Example 7 is that the perovskite film is not passivated, and the ternary perovskite film (FA x is directly prepared on the NiO0.83 MA 0.17 ) 0.95 Cs 0.05 Pb(I 0.9 Br 0.1 )3 is used as the active perovskite layer. The specific steps are as follows: Spin-coat the perovskite precursor solution of the ternary system (FA 0.83 MA 0.17 ) 0.95 Cs 0.05 Pb(I 0.9 Br 0.1 )3) statically at 1300 rpm for 5 s, then accelerate to 5000 rpm at an acceleration of 2000 rpm and hold for 40 s. Drop the antisolvent anisole in the last 5 s, and then perform post-annealing treatment at 100 °C for 30 min to form a perovskite film.

[0162] Test the relevant performance indicators of the optoelectronic devices in the above examples and comparative examples under the same test conditions (all device tests are carried out under the environmental conditions of room temperature and 40% humidity). The results are as follows in the table:

[0163]

[0164]

[0165] As can be seen from the table, compared with the comparative example, the power conversion efficiency (PCE) of the example has been significantly improved.

[0166] Figure 1 It is the crystallization intermediate phase diagram of the perovskite bulk phase of Comparative Example 2. Figure 2 It is the crystallization intermediate phase diagram of adding TFPEA to the perovskite bulk phase of Example 4. Figure 3 It is the crystallization intermediate phase diagram of adding EBTP to the perovskite bulk phase of Example 5. As can be seen from the figure, after adding TFPEA / EBTP, the needle-like defects are significantly reduced, and the nucleation and crystallization quality are improved.

[0167] Figure 4 From left to right are the scanning electron microscope images of Comparative Example 2, Example 4, and Example 11. As can be seen from the figure, after adding TFPEA to the bulk phase, the perovskite grain quality is significantly improved compared with the comparative example; at the same time, after adding TFPEA to the bulk phase and the interface, while the perovskite grain quality is improved, the interface is more dense and the interface defects are reduced.

[0168] Figure 5 It is the in-situ PL spectrum of the perovskite bulk phase of Comparative Example 2. Figure 6 It is the in-situ PL spectrum of adding TFPEA to the perovskite bulk phase of Example 1. As can be seen from the figure, after the perovskite film turns black, the film quality is improved.

[0169] Figure 7 The left is the contact angle diagram of the perovskite bulk phase of Comparative Example 2, and the right is the contact angle diagram of the perovskite bulk phase with TFPEA added in Example 2. As can be seen from the figure, the contact angle between the perovskite film and water increases, enhancing the humidity resistance of the film.

[0170] The above embodiments are only used to further illustrate a perovskite bulk phase passivation method and application of the present invention, but the present invention is not limited to the embodiments. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention all fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for passivating a perovskite bulk phase, characterized in that: The following steps are involved: S1: dissolving a functional organic molecule in a non-protonic polar solvent to prepare a passivating agent mother solution; the functional organic molecule is an aromatic compound composed of a Lewis acid functional group and a Lewis base functional group with a certain spatial position distribution, wherein the Lewis acid functional group and the Lewis base functional group are separated by a single or multiple aromatic rings and appear in a non-ortho position; S2: adding the passivating agent mother solution obtained in S1 to the perovskite precursor solution to obtain a perovskite precursor solution mixture; S3: using the perovskite precursor solution mixture obtained in S2, a wet preparation process is adopted to form a passivated perovskite film by coating, desolvation and post-annealing.

2. The perovskite bulk phase passivation method according to claim 1, characterized in that: The Lewis acid functional group includes at least one of a boric acid group, a phosphoric acid group, and a fluorine-containing group; the Lewis base functional group includes at least one of a carbonyl group, an ether group, an ester group, an amine, a phosphoryl group, pyridine, and derivatives thereof.

3. The perovskite bulk phase passivation method according to claim 1, characterized in that: The functional organic molecule is at least one of diethyl trifluoromethylphenyl phosphate, bis(p-trifluoromethylphenyl)ethyl phosphate, and diethyl p-aminophenyl phosphate.

4. The perovskite bulk phase passivation method according to claim 1, characterized in that: The aprotic polar solvent includes at least one of acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, and N-ethylpyrrolidone.

5. The perovskite bulk phase passivation method according to claim 1, characterized in that: The concentration of the functional organic molecule in the perovskite precursor solution mixture is 0.8-1.2 mg / mL.

6. The perovskite bulk phase passivation method according to claim 1, characterized in that: In step S3, the perovskite film is formed on a hole transport layer or an electron transport layer of a perovskite solar cell, or on a hole transport layer or an electron transport layer having a passivation layer surface; wherein the passivation layer is formed by the passivator mother solution.

7. The perovskite bulk phase passivation method according to claim 1, characterized in that: The perovskite precursor solution is used to prepare at least one type of the following ABX3 configuration perovskite film: i. Organic-inorganic perovskite films, wherein the A-site cations include formamidine (FA + ), methylamine (MA + ) or cesium (Cs + ), rubidium (Rb + ) at least one of the following, the B-site ions include Pb 2+ Sn 4+ , X-site ions include I - , Cl - Br - One or more of; ii. Pure inorganic perovskite film, where the A-site cation is Cs + , B-site ions include Pb 2+ Sn 4+ At least one of the X-site ions includes I - , Cl - Br - One or more of .

8. The perovskite bulk phase passivation method according to claim 1, characterized in that: The thickness of the perovskite film is 100-500 nm.

9. The perovskite bulk phase passivation method according to claim 1, characterized in that: The post-annealing method is thermal annealing or infrared assisted annealing, wherein: The thermal annealing temperature range is 100-150°C, and the post-annealing time is 10-60min; The infrared assisted annealing is to place the desolvated wet film in the chamber of the infrared assisted annealing equipment, raise the chamber temperature to 300-350° C. within 35 seconds, and then cool naturally to 20-30° C.

10. A perovskite solar cell, characterized in that: The method comprises a bottom electrode, a hole transport layer, a perovskite active layer, an electron transport layer and a top electrode, wherein the perovskite active layer is formed by the perovskite bulk phase passivation method according to any one of claims 1 to 9.

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