Tin-based perovskite material and preparation method and application thereof

Abstract

The invention belongs to the technical field of tin-based perovskite, and particularly relates to a tin-based perovskite material and a preparation method and application thereof. The tin-based perovskite material is a lead-free tin-based perovskite precursor solution and an aniline hypophosphorous acid additive; wherein the aniline hypophosphorous acid additive accounts for 0.04%-0.12% of the mass of the tin-based perovskite material. The aniline hypophosphorous acid additive is added into the tin-based perovskite material, the hypophosphorous acid functional group of the additive has high reducibility, and the behavior that Sn < 2 + > in tin-based perovskite is oxidized into Sn < 4 + > can be effectively inhibited. Meanwhile, hydrogen bond interaction among iodide ions in the amino tin-based perovskite of the additive can further form a hydrogen bond network, so that crystal defects of the tin-based perovskite are reduced, the carrier recombination behavior is inhibited, and the mobility barrier of the iodide ions is improved. The benzene ring is a rigid molecule, has certain hydrophobic property, and is beneficial to enhancing the moisture resistance of the tin-based film.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of tin-based perovskite, and particularly relates to a tin-based perovskite material (lead-free tin-based perovskite material) and a preparation method and application thereof. BACKGROUND

[0002] In the global energy clean competition, perovskite solar cells become the first choice in new solar technologies with the advantages of high efficiency, low cost and easy processing. However, the core material of the existing perovskite technology system contains lead, and lead-based perovskite material may leak in the production, use and recycling process, causing irreversible harm to the ecological environment and biological health. With the improvement of human awareness of environmental protection and sustainable development, the development of lead-free and eco-friendly perovskite material has become a major demand in the technical field. Compared with lead-based perovskite, tin-based perovskite, which also has excellent photoelectric properties and is eco-friendly, is obviously a truly environmentally friendly and full life cycle safe perovskite material. Therefore, tin-based perovskite is considered as the most potential lead-free alternative material system due to its ideal band gap, high mobility and good environmental compatibility.

[0003] However, tin-based perovskite material also faces many challenges in practical application. Tin ions (Sn 2+ ) in tin-based perovskite material have strong reducing property and are easily oxidized to tin tetravalent ions (Sn 4+ ) in the air, which introduces a large number of deep level defects, causes serious non-radiative recombination behavior, accelerates the degradation and performance deterioration process of tin-based perovskite material, and greatly reduces the efficiency and long-term stability of tin-based perovskite optoelectronic devices. Therefore, it is of great significance to develop a preparation method capable of improving the stability of tin-based perovskite material, preparing high-quality thin film and improving the photoelectric performance, for promoting the practical application of tin-based perovskite material in the field of solar energy. SUMMARY

[0004] Therefore, the present application aims to provide a tin-based perovskite material (lead-free tin-based perovskite material) and a preparation method and application thereof.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions: A tin-based perovskite material, the tin-based perovskite material is a lead-free tin-based perovskite precursor solution and an aniline hypophosphorous acid additive; wherein the aniline hypophosphorous acid additive accounts for 0.04% to 0.12% of the mass of the tin-based perovskite material.

[0006] The aniline hypophosphorous acid additive is one or several of phenyl hypophosphorous acid, aniline hypophosphorous acid, diamine phenyl hypophosphorous acid, phenyl hypophosphorous acid salt, aniline hypophosphorous acid salt and diamine phenyl hypophosphorous acid salt.

[0007] The lead-free tin-based perovskite precursor in the lead-free tin-based perovskite precursor solution is a metal halide and an organic salt, the metal halide is SnX2 and SnF2, and the organic salt is AX; wherein A is CH3NH2, X is one or more of I, Br, and Cl, and the halogens in the metal halide and the organic salt can be the same or different.

[0008] Further, the raw materials of the lead-free tin-based perovskite precursor are SnI2, FAI, PEAI, SnF2, and SCNNH4, and the molar ratio of each raw material can be 1:1:0:0.07:0.06, 1:0.98:0.02:0.07:0.06, 1:0.96:0.04:0.07:0.06, 1:0.94:0.06:0.07:0.06, 1:0.92:0.08:0.07:0.06, or 1:0.90:0.10:0.07:0.06.

[0009] The lead-free tin-based perovskite precursor solution is obtained by mixing the lead-free tin-based perovskite precursor with a mixed solution, wherein the final concentration of the lead-free tin-based perovskite precursor in the lead-free tin-based perovskite precursor solution is 0.9-1.5 mol / L, and the mixed solution is DMF and DMSO; wherein the volume ratio of DMF to DMSO is (8-9):(2-1).

[0010] The tin-based perovskite material is obtained by mixing the lead-free tin-based perovskite precursor solution and the solution containing the aniline hypophosphorous acid additive according to the above proportions.

[0011] The mixing is performed at room temperature by magnetic stirring for about 6 hours or by heating stirring at 55°C for about 1 hour.

[0012] The application of the tin-based perovskite material, which is used in the field of solar cells.

[0013] A photovoltaic cell device, the cell device sequentially stacks a substrate, a hole extraction layer, a tin-based perovskite active layer, an electron extraction layer, and a metal electrode layer, and the cell device contains the tin-based perovskite active layer formed by the tin-based perovskite material of claim 1.

[0014] The tin-based perovskite active layer is obtained by coating the tin-based perovskite material on the surface of the SAM layer and performing two-step annealing treatment, thereby forming a tin-based perovskite active layer film.

[0015] The tin-based perovskite active layer film contains ASnX3, wherein A is CH3NH2, and X is one or two of I, Br, and Cl.

[0016] The coating adopts a reverse solvent assisted spin coating method; the spin coating is two-step spin coating, the first step speed is 1000 rmp / s, the time is 10 s, the acceleration is 200~500 rmp / s, the second step speed is 5000 rmp / s, the time is 30 s, and the acceleration is 1000~2500 rmp / s; the time for spraying the reverse solvent is the 11th second of the second step; and the reverse solvent is chlorobenzene.

[0017] The annealing is step-by-step annealing, and the annealing temperatures are 60 DEG C and 70 DEG C respectively, and the corresponding annealing times are 3 min and 10 min respectively.

[0018] The thickness of the tin-based perovskite film is 280~350 nm.

[0019] The sheet resistance of the anode is 15 Ω, and the light transmittance is 88%; the thickness of the hole extraction layer is 30 nm; the thickness of the electron transport layer is 25 nm; the thickness of the hole blocking layer is 5 nm; and the thickness of the metal electrode is 90~150 nm.

[0020] The lead-free tin-based perovskite solar cell is of an inverted structure.

[0021] Compared with the prior art, the present application has the following beneficial effects: The aniline hypophosphorous acid substance is added to the lead-free tin-based perovskite precursor solution as an additive, can effectively control the perovskite crystallization growth, specifically promotes the nucleation process, slows down the subsequent grain growth process, and then obtains a perovskite light-absorbing layer with large grain size and vertical crystal orientation; specifically: 1) The molecule of the aniline hypophosphorous acid substance contains a unique functional group of amino, hypophosphorous acid and benzene ring, and can realize multifunctional passivation effect. The amino group can form a hydrogen bond grid with the iodine ions in the perovskite lattice, passivate halogen vacancy defects and increase the potential barrier of halogen ions. Hypophosphorous acid can inhibit the oxidation behavior of Sn 2+ in perovskite and form coordination with it. In addition, aniline hypophosphorous acid can also control the crystallization growth kinetics, accelerate nucleation and slow down growth, which is beneficial to realize high-quality lead-free tin-based perovskite material with large grain size, few grain boundaries and long carrier lifetime, and effectively improve the photoelectric conversion efficiency of the tin-based perovskite solar cell.

[0022] 2) The aniline hypophosphorous acid substance has certain rigidity and hydrophobicity due to the presence of benzene ring (π-conjugated molecule), which further enhances the crystalline quality and air stability of the lead-free tin-based perovskite material, and thus improves the open-circuit voltage, fill factor and photoelectric conversion efficiency of the tin-based perovskite solar cell.

[0023] 3) The aniline hypophosphite substance is low in manufacturing cost and widely available. Compared with other additives or passivation processes in the prior art, the aniline hypophosphite salt as an additive can not only effectively passivate the internal defects of the perovskite crystal, but also induce perovskite crystallization kinetics, so that a perovskite light-absorbing layer with large crystal grains and few grain boundaries is obtained, and the photoelectric conversion efficiency and operating stability of the perovskite solar cell are further improved, which is more conducive to improving the performance of the perovskite solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a structural schematic diagram of an inverted tin-based perovskite solar cell provided by an embodiment of the present application.

[0025] Figure 2 is a UV-visible light absorption spectrum of a tin-based perovskite provided by an embodiment of the present application.

[0026] Figure 3 is an XRD diagram of tin-based perovskites of Comparative Example 1 and Example 2 provided by the present application.

[0027] Figure 4 is a fluorescence spectrum diagram of tin-based perovskites of Comparative Example 1 and Example 2 provided by the present application.

[0028] Figure 5 is an XPS diagram of tin-based perovskites of Comparative Example 1 and Example 2 provided by the present application, wherein (a) is a tin-based perovskite of Comparative Example 1 without aging and a tin-based perovskite of Comparative Example 1 after aging in air (humidity 40%) for 60 minutes; (b) is a tin-based perovskite of Example 2 without aging and a tin-based perovskite of Example 2 after aging in air (humidity 40%) for 60 minutes; (the humidity is the real-time humidity value in the recording laboratory air).

[0029] Figure 6 is an SEM diagram of tin-based perovskites of Comparative Example 1 and Example 2 provided by the present application, wherein (a) is a new tin-based perovskite of Comparative Example 1, (b) is a tin-based perovskite of Example 2 after air aging; (c) is a new tin-based perovskite of Example 2, and (d) is a tin-based perovskite of Example 2 after aging in air.

[0030] Figure 7 is a grain size distribution diagram of the crystal grains of tin-based perovskites of Comparative Example 1 and Example 2 provided by the present application.

[0031] Figure 8 is a voltage-current density curve diagram of a photovoltaic device corresponding to a tin-based perovskite of Comparative Example 1 and Examples 1-3 provided by the present application. DETAILED DESCRIPTION

[0032] The specific embodiments of the present application are further described in the following examples, which serve to illustrate the general principles of the application. It is to be understood that this is merely an aid to understanding the present application and is not intended to limit the application as described.

[0033] Other features and advantages of the present application will become more apparent from the following detailed description of exemplary embodiments thereof, when taken in conjunction with the accompanying drawings, which together illustrate some of the principles of the present application.

[0034] The present application discloses a lead-free tin-based perovskite material (thin film) and a preparation method and application thereof. 2+ The prepared lead-free tin-based perovskite material is more stable and has a larger grain size.

[0035] A phenyl hypophosphorous acid substance is added to the precursor solution as an additive, and the hypophosphorous acid functional group of the additive has strong reducing property, which can effectively inhibit the oxidation of Sn 2+ in the tin-based perovskite to Sn 4+ Meanwhile, the hydrogen bond interaction between the iodine ions in the additive and the tin-based perovskite can further form a hydrogen bond network, further reduce the crystal defects of the tin-based perovskite, inhibit the carrier recombination behavior, and improve the iodine ion migration potential barrier. The benzene ring is a rigid molecule and has certain hydrophobic properties, which is beneficial to enhancing the moisture resistance of the tin-based thin film. Meanwhile, the additive can also regulate the dynamic competition process of nucleation and growth of the perovskite material, promote the grain coarsening in the precursor solution of the tin-based perovskite material, and improve the crystallization quality, thereby enhancing the oxygen resistance and photovoltaic properties of the tin-based perovskite material.

[0036] The preparation method of the tin-based perovskite material comprises the following steps: The lead-free tin-based perovskite precursor solution and the solution containing the aniline hypophosphorous acid additive are mixed in the above proportions to obtain the tin-based perovskite material.

[0037] After the tin-based perovskite material solution (containing the additive) is coated on the surface of the substrate, distribution annealing treatment is performed to obtain the tin-based perovskite active layer thin film.

[0038] In the present application, all the raw materials for preparation are market products familiar to those skilled in the art and do not need further processing, unless otherwise specified.

[0039] The lead-free tin-based perovskite precursor solution is obtained by mixing a lead-free tin-based perovskite precursor with a mixed solution, wherein the final concentration of the lead-free tin-based perovskite precursor in the lead-free tin-based perovskite precursor solution is 0.9-1.5 mol / L, and more preferably 0.9 mol / mL, 0.95 mol / mL, 1.0 mol / mL or 1.5 mol / mL. In an embodiment of the present application, the concentration of the tin-based perovskite material in the tin-based perovskite solution can be 0.95 mol / mL. The mixed solution is DMF and DMSO, and the volume ratio of DMF to DMSO is (8-9):(2-1), and more preferably 8:2, 8.2:1.8, 8.4:1.6, 8.6:1.4, 8.8:1.2 or 9:1. In an embodiment of the present application, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide can be 9:1.

[0040] The lead-free tin-based perovskite precursor preferably comprises formamidinium hydriodide, tin diiodide, 2-phenylethylamine hydriodide, tin difluoride and ammonium thiocyanate, and the molar ratio of the formamidinium hydriodide, tin diiodide, 2-phenylethylamine hydriodide, tin difluoride and ammonium thiocyanate is preferably 1:1:0:0.07:0.06, 1:0.98:0.02:0.07:0.06, 1:0.96:0.04:0.07:0.06, 1:0.94:0.06:0.07:0.06, 1:0.92:0.08:0.07:0.06 or 1:0.90:0.10:0.07:0.06. In an embodiment of the present application, the molar ratio of the formamidinium hydriodide, tin diiodide, 2-phenylethylamine hydriodide, tin difluoride and ammonium thiocyanate can be 1:0.9:0.1:0.07:0.06.

[0041] Preferably, the preparation method of the lead-free tin-based perovskite precursor solution preferably comprises: dissolving tin diiodide, formamidinium hydriodide, tin difluoride, 2-phenylethylamine hydriodide and ammonium thiocyanate in a mixed solution to obtain the lead-free tin-based perovskite precursor. The mixed solution is DMF and DMSO (volume ratio 9:1).

[0042] The introduction of tin difluoride and ammonium thiocyanate in the above-mentioned lead-free tin-based perovskite precursor is beneficial to improve the tin-based perovskite crystallization growth process, improve the quality and oxygen resistance of the perovskite material, and facilitate the preparation of tin-based perovskite thin films with better stability.

[0043] The solution containing aniline hypophosphorous acid-based additives is obtained by adding additives to a solvent, and the solvent is N,N-dimethylformamide.

[0044] The lead-free tin-based perovskite precursor solution and the solution containing aniline hypophosphite additives are mixed according to the above proportions, and then stirred at room temperature and in the dark. The stirring speed is preferably 6500-1000 rpm, more preferably 650 rpm, 750 rpm, 850 rpm, 950 rpm, or 1050 rpm. In an embodiment of the present invention, the stirring speed can be 850 rpm; the stirring time is preferably 1-2 h, more preferably 1 h, 1.5 h, or 2 h. In an embodiment of the present invention, the stirring time can be 1.5 h. In the present invention, the mixing is carried out at room temperature and in the dark to ensure that aniline hypophosphite is completely dissolved in the tin-based perovskite solution, while avoiding Sn... 2+ and I - Oxidation.

[0045] The tin-based perovskite active layer is formed by coating the tin-based perovskite material onto the surface of the SAM layer and then performing a two-step annealing process.

[0046] The spin coating preferably includes a first spin coating and a second spin coating performed sequentially; the rotation speed of the first spin coating is preferably 800~1100 rpm, more preferably 800 rpm, 900 rpm, 100 rpm, or 1100 rpm; in an embodiment of the present invention, the rotation speed of the first spin coating can be 1000 rpm; the time is preferably 8~12 s, more preferably 8 s, 9 s, 10 s, 11 s, or 12 s; in an embodiment of the present invention, the time of the first spin coating can be 10 s; the rotation speed of the second spin coating is preferably 4500~5500 rpm, more preferably 4500 rpm, 4600 rpm, 4700 rpm, 4800 rpm, 4900 rpm, 5000 rpm, 5100 rpm, 5200 rpm, 5300 rpm, 5400 rpm, or 5500 rpm; the time is preferably 25~35 s, more preferably 25 s, 26 s, or 27 s. The spin coating time can be 28 s, 29 s, 30 s, 31 s, 32 s, 33 s, 34 s or 35 s; in an embodiment of the present invention, the spin coating speed can be 5000 rpm and the time can be 30 s.

[0047] At the 21st second of the spin coating process, an antisolvent is preferably added dropwise. In this invention, the antisolvent is preferably chlorobenzene. Adding an antisolvent dropwise during the spin coating process facilitates the rapid evaporation of the solvent in the perovskite solution, thereby accelerating nucleation and crystal growth. This promotes the formation of the δ-phase perovskite and improves the thin film quality, ultimately enhancing the overall performance and air stability of the lead-free tin-based perovskite solar cell.

[0048] The annealing process is a step-by-step annealing. The initial annealing temperature is preferably 60°C, and the time is preferably 3-5 min, more preferably 3 min, 4 min, or 5 min. The second annealing temperature is preferably 70°C, and the time is preferably 8-15 min, more preferably 8 min, 10 min, 12 min, or 14 min. In an embodiment of the present invention, the two-step annealing process can be performed at 60°C for 3 min and at 70°C for 10 min.

[0049] The present invention also provides a tin-based perovskite active layer film prepared by the preparation method described in the above technical solution.

[0050] The grain size of the perovskite crystals in the tin-based perovskite active layer film is preferably 129.04~188.14 nm, more preferably 188.14 nm. The grain size distribution of the perovskite crystals in the perovskite light-absorbing layer is uniform.

[0051] The present invention also provides the application of the perovskite light-absorbing layer described above in perovskite solar cells.

[0052] In this invention, the perovskite solar cell is preferably an inverted perovskite solar cell.

[0053] In this invention, the inverted perovskite solar cell preferably comprises, sequentially arranged, a conductive substrate, a hole transport layer 1, a hole transport layer 2, a perovskite light-absorbing layer, an electron transport layer 1, an electron transport layer 2, and a metal electrode layer (such as...). Figure 1 (As shown).

[0054] The conductive substrate is preferably ITO conductive glass. Before use, the conductive substrate is preferably pretreated. The pretreatment typically involves sequentially ultrasonically cleaning the etched ITO conductive glass in ultrapure water, ethanol, and isopropanol for 30 minutes, followed by drying with nitrogen and then treating it in an ultraviolet ozone environment for 20 minutes.

[0055] The thickness of the hole transport layer 1 is preferably 35-45 nm, more preferably 40 nm. In an embodiment of the present invention, the thickness of the hole transport layer 1 can be 40 nm.

[0056] The hole transport layer 1 is preferably made of nickel oxide. The preparation method of the hole transport layer 1 preferably includes the following steps: coating a nickel oxide solution onto the surface of the conductive substrate, followed by annealing to obtain the hole transport layer 1.

[0057] The preparation of the tin oxide precursor solution preferably includes: dissolving 10 mg of nickel oxide in 1 mL of ultrapure water, and sonicating in a chamber for 10 min to obtain the nickel oxide aqueous solution.

[0058] The spin coating speed is preferably 1500~5000 rpm, more preferably 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm, or 5000 rpm; the time is preferably 20~30 s, more preferably 20 s, 25 s, or 30 s. In an embodiment of the present invention, the spin coating speed can be 3000 rpm, and the time can be 25 s.

[0059] The annealing temperature is preferably 130~150 ℃, more preferably 130 ℃, 140 ℃, or 150 ℃; the time is preferably 10~20 min, more preferably 10 min, 15 min, or 20 min. In the embodiments of the present invention, the annealing temperature can be 150 ℃ and the time can be 10 min.

[0060] The water in the nickel oxide aqueous solution needs to be evaporated quickly by high-temperature annealing, which promotes the crystallization process and forms a smooth and dense hole transport layer.

[0061] The hole transport layer 1 is preferably made of nickel oxide. In this invention, the method for preparing the hole transport layer 1 preferably includes the following steps: coating a nickel oxide solution onto the surface of the conductive substrate and then annealing it to obtain the hole transport layer 1.

[0062] The preparation of the tin oxide precursor solution preferably includes: dissolving 10 mg of nickel oxide in 1 mL of ultrapure water, and sonicating in a chamber for 10 min to obtain the nickel oxide aqueous solution.

[0063] The spin coating speed is preferably 1500~5000 rpm, more preferably 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm, or 5000 rpm; the time is preferably 20~30 s, more preferably 20 s, 25 s, or 30 s. In an embodiment of the present invention, the spin coating speed can be 3000 rpm, and the time can be 25 s.

[0064] The annealing temperature is preferably 130~150 ℃, more preferably 130 ℃, 140 ℃, or 150 ℃; the time is preferably 10~20 min, more preferably 10 min, 15 min, or 20 min. In the embodiments of the present invention, the annealing temperature can be 150 ℃ and the time can be 10 min.

[0065] After obtaining the nickel oxide hole transport layer, the present invention preferably further includes ultraviolet ozone treatment of the nickel oxide hole transport layer. The present invention does not have any special limitations on the process of ultraviolet ozone treatment, and any process known to those skilled in the art can be used.

[0066] In this invention, the material of the hole transport layer 2 is preferably [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz). In this invention, the preparation method of the hole transport layer 2 preferably includes the following steps: coating a SAM solution onto the surface of the nickel oxide substrate, followed by annealing, to obtain the hole transport layer 2.

[0067] The concentration of the MeO-2PACz solution is preferably 0.3~0.5 mg / mL, more preferably 0.3 mg / mL, 0.4 mg / mL or 0.5 mg / mL. In embodiments of the present invention, the concentration of the MeO-2PACz solution can be 0.5 mg / mL; the method for preparing the SAM solution preferably includes: dissolving MeO-2PACz in ethanol to obtain the MeO-2PACz solution.

[0068] The spin coating speed is preferably 3000~5000 rpm, more preferably 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm or 5000 rpm; the spin coating time is preferably 20~30 s, more preferably 20 s, 25 s or 30 s. In an embodiment of the present invention, the spin coating speed can be 4000 rpm and the spin coating time can be 30 s.

[0069] The annealing temperature is preferably 100-120 ℃, more preferably 100 ℃, 110 ℃, or 120 ℃; the time is preferably 8-12 min, more preferably 8 min, 10 min, or 12 min. In the embodiments of the present invention, the annealing temperature can be 100 ℃ and the time can be 10 min.

[0070] The method for preparing the perovskite light-absorbing layer is preferably the same as the method described in the above technical solution, and will not be repeated here.

[0071] The thickness of the electron transport layer is preferably 20-30 nm, more preferably 25 nm.

[0072] The electron transport layer is preferably a C60 electron transport layer.

[0073] The preferred method for preparing the electron transport layer is vacuum thermal evaporation. This invention does not impose any special limitations on the vacuum thermal evaporation process; any process well known to those skilled in the art can be used.

[0074] The thickness of the electronically modified layer is preferably 4-7 nm, more preferably 5 nm.

[0075] The electronic modification layer is preferably a BCP electronic modification layer.

[0076] The preferred method for preparing the electronic modification layer is vacuum thermal evaporation. This invention does not impose any special limitations on the vacuum thermal evaporation process; any process well known to those skilled in the art can be used.

[0077] The thickness of the metal electrode layer is preferably 90~150 nm, more preferably 100 nm.

[0078] The metal electrode layer is preferably a silver electrode layer.

[0079] The preferred method for preparing the metal electrode layer is vacuum thermal evaporation. This invention does not impose any special limitations on the vacuum thermal evaporation process; any process well-known to those skilled in the art can be used.

[0080] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0081] Compare with Example 1: ITO conductive glass ( (15 Ω, light transmittance 88%) was ultrasonically cleaned sequentially with deionized water, isopropanol and ethanol solutions, with each cleaning time being 20 min. After drying with clean nitrogen gas, it was transferred to an ultraviolet ozone cleaning device for cleaning for 20 min to obtain clean and hydrophilic ITO transparent conductive glass, ready for use.

[0082] Take 25 μL of nickel oxide aqueous solution and spin-coat it onto the surface of the pretreated ITO transparent conductive glass substrate. The spin-coating process is: 3000 rpm for 30 s. After the process is completed, immediately transfer it to a 150℃ heating stage for annealing for 10 min to form a dense hole transport layer 1.

[0083] After spin-coating MeO-2PACz solution (MeO-2PACz solution is 0.5 mg / mL MeO-2PACz ethanol solution, spin-coating speed is 3000 rpm, time is 30 s) onto the hole transport layer 1, it is annealed at 100 ℃ for 10 min to obtain hole transport layer 2.

[0084] A tin-based perovskite material solution was spin-coated onto the surface of the hole transport layer (the tin-based perovskite material solution consisted of 17.797 mg PEAI, 154.773 mg FAI, 372.52 mg SnI2, 11.753 mg SnF2, and 5.33 mg NH4SCN dissolved in a mixed solvent of 900 μL DMF and 100 μL DMSO; the spin-coating process was as follows: spin-coating at 1000 rpm for 10 s, followed by spin-coating at 5000 rpm for 30 s), and adding 350 μL chlorobenzene as an anti-solvent at the 21st s of the spin-coating, annealing at 60 °C for 3 min, and then annealing at 70 °C for 10 min to obtain a tin-based perovskite active layer film with perovskite light absorption.

[0085] Vacuum thermal evaporation is used (at a vacuum level of approximately 10). -7 Under Torr conditions (at a rate of 0.2 Å / s), C60 was deposited on the surface of the perovskite light-absorbing layer to obtain a C60 electron transport layer (25 nm thick).

[0086] Vacuum thermal evaporation is used (at a vacuum level of approximately 10). -7 Under Torr conditions, BCP is deposited on the surface of the C60 electron transport layer to obtain a BCP electron modification layer (with a thickness of 5 nm).

[0087] Vacuum thermal evaporation is used (at a vacuum level of approximately 10). -7 Under Torr conditions, a silver electrode (100 nm thick) is deposited on the surface of the BCP electronic modification layer to obtain a lead-free tin-based perovskite solar cell.

[0088] Depend on Figure 1 A schematic diagram of the inverted device, from bottom to top: ITO conductive glass, hole transport layer 1 (NiO). X The structure consists of a hole transport layer 2 (MeO-2PACz), a lead-free tin-based perovskite layer, an electron transport layer 1 (C60), an electron transport layer 2 (BCP), and a metal electrode.

[0089] Example 1 Referring to Comparative Example 1, the difference is that: the tin-based perovskite material solution used in preparing the tin-based perovskite active layer film was prepared by adding aniline hypophosphite solution to the lead-free tin-based perovskite precursor solution described in Comparative Example 1. The aniline hypophosphite solution was prepared by adding aniline hypophosphite to DMF solution (10 mg / mL). The amount of aniline hypophosphite solution added to the lead-free tin-based perovskite precursor solution was 25 μL, and the volume was adjusted to 1 mL. The precursor substances in the lead-free tin-based perovskite precursor solution were the same as those described in the Comparative Example in terms of composition and amount. The mixed solution contained 875 μL of DMF and 100 μL of DMSO.

[0090] Example 2 Referring to Comparative Example 1, the difference is that: the tin-based perovskite material solution used in preparing the tin-based perovskite active layer film is to add aniline hypophosphite solution to the lead-free tin-based perovskite precursor solution described in Comparative Example 1. The aniline hypophosphite solution is aniline hypophosphite added to DMF solution (10 mg / mL). The amount of aniline hypophosphite solution added to the lead-free tin-based perovskite precursor solution is 50 μL, and the volume is adjusted to 1 mL. The precursor substances in the lead-free tin-based perovskite precursor solution are the same as those described in the Comparative Example in terms of composition and amount. The mixed solution contains 850 μL of DMF and 100 μL of DMSO.

[0091] Example 3 Referring to Comparative Example 1, the difference is that: the tin-based perovskite material solution used in preparing the tin-based perovskite active layer film was prepared by adding aniline hypophosphite solution to the lead-free tin-based perovskite precursor solution described in Comparative Example 1. The aniline hypophosphite solution was prepared by adding aniline hypophosphite to DMF solution (10 mg / mL). The amount of aniline hypophosphite solution added to the lead-free tin-based perovskite precursor solution was 75 μL, and the volume was adjusted to 1 mL. The precursor substances in the lead-free tin-based perovskite precursor solution were the same as those described in the Comparative Example in terms of composition and amount. The mixed solution contained 825 μL of DMF and 100 μL of DMSO.

[0092] The ultraviolet-visible absorption spectra of the tin-based perovskite active layer films prepared in the above embodiments and comparative examples were measured. See [link to relevant documentation]. Figure 2 , Among them, the ultraviolet-visible absorption spectra of the tin-based perovskite materials described in Comparative Example 1 (0 μL), Example 1 (25 μL), Example 2 (50 μL), and Example 3 (75 μL) are obtained by... Figure 2 It can be seen that the absorption of ultraviolet and visible light is enhanced in all embodiments. At the same time, the absorption intensity of the perovskite light-absorbing layer in Example 2 is significantly enhanced compared with that of the perovskite material in Control Example 1 and other embodiments, indicating that aniline hypophosphite effectively reduces the defect density of tin-based perovskite material. Then, the tin-based perovskite active layer films prepared in Example 2 and Comparative Example 1 were further tested. Figure 3 The XRD spectra in Example 2 show that the diffraction intensities of the (100) and (200) crystal planes of the tin-based perovskite material are significantly increased compared to those of the tin-based perovskite material in Comparative Example 1. Simultaneously, the position of the diffraction peak on the (001) crystal plane shifts to a smaller angle, and the full width at half maximum (FWHM) decreases from 0.181° to 0.156°. The narrower FWHM indicates that aniline hypophosphite promotes the improvement of the crystallinity quality of the tin-based perovskite film.

[0093] Depend on Figure 4 The PL spectrum shows that the PL intensity of the perovskite absorbing layer in Example 2 is significantly increased compared with that of the perovskite material in Control Example 1, and the half-peak width is narrower, indicating that aniline hypophosphite effectively passivates the defects in the tin-based perovskite material and promotes the uniform distribution of grains. The tin-based perovskite active layer films prepared in Example 2 and Comparative Example 1 were then subjected to aging tests under the following conditions: aging for 60 minutes in air with a humidity of 40%.

[0094] Depend on Figure 5 It can be seen that Sn in Control Example 1 and Experimental Example 2 was quantified using XPS. 2+ Ion oxidation behavior, as shown in Figure a, compares Sn in Control Example 1 (lead-free tin-based perovskite material) after aging in air for 0 minutes. 2+ With a content of 83.87%, Sn was aged for 60 minutes in air with 40% humidity. 2+ The content decreased to 11.40%. And Sn... 4+ The content increased dramatically from 16.13% before aging to 88.60%. After aging in air for 0 minutes, the Sn content of the treated lead-free tin-based perovskite material in Example 2 increased dramatically. 2+ With a content of 87.20%, Sn was aged for 60 minutes in air with 40% humidity. 2+ The Sn4+ content decreased to 71.84.40%. However, the Sn4+ content increased from 12.80% before aging to 28.16%. This is higher than the Sn4+ content in the aged lead-free tin-based perovskite material in Control Example 1. 4+ Compared to the peak intensity, Sn in the lead-free tin-based perovskite material of Experimental Example 2 4+ The content decreased from 88.60% to 28.16%. This indicates that the Sn content on the surface of the treated tin-based perovskite film has decreased. 2+ Oxidation behavior was significantly suppressed, extending the stability of tin-based perovskite materials (films).

[0095] And by Figure 6 As can be seen from the scanning electron microscope image, Figure 6In Comparative Examples 1 (a and b), the perovskite light-absorbing layer contains white crystals and excessive pinholes; in Example 1, the white crystals in the perovskite are reduced and the pinholes disappear. This is because in Example 1, the incorporation of aniline hypophosphite indicates that the perovskite light-absorbing layer doped with aniline hypophosphite crystallizes more fully and has higher crystal quality. Figure 6 c and 6d are electron micrographs of the tin-based perovskite films of Control Example 1 and Experimental Example 2, respectively, after aging in air with 35% humidity for 1 hour. Figure 6 Severe degradation of the thin film in c, Figure 6 The degradation of d was significantly improved, mainly due to the effective inhibition of Sn by hypophosphite. 2+ The oxidation process effectively enhances the stability (oxidation resistance) of tin-based perovskite films.

[0096] Depend on Figure 7 The statistical distribution of particle size in the scanning electron microscope images of the tin-based perovskite materials described in Comparative Example 1 and Example 2 (statistics from...) Figure 6 According to the statistical distribution diagram of particle size (a and 6c), it can be seen that the grain size in Example 2 is larger and more uniformly distributed.

[0097] The tin-based perovskite solar cells prepared in the above embodiments and comparative examples were then tested under standard simulated solar light irradiation. The specific parameters were as follows: in an N2 atmosphere, under standard AM 1.5G illumination, the starting voltage was -0.1V, the ending voltage was 1.2V, the number of measurement points was 50, the delay time was 0.01s, the limiting current was 1A, and the irradiation area was 0.032cm². 2 .

[0098] Depend on Figure 8 As can be seen, the highest photoelectric conversion efficiency was achieved when the additive was a 50 μL aniline hypophosphite DMF solution. The test results for devices with different additive amounts are summarized in Table 1.

[0099] Table 1 shows the performance parameters of tin-based perovskite solar cells in Comparative Example 1 and Examples 1-3.

[0100] In summary, compared with perovskite solar cells without aniline hypophosphite, the perovskite material in the lead-free tin-based perovskite solar cell with added aniline hypophosphite described in this invention has a significantly increased grain size, a significantly reduced number of grain boundaries, and a significantly improved morphology of the tin-based perovskite light-absorbing layer. Consequently, the open-circuit voltage, fill factor, and photoelectric conversion efficiency of the perovskite solar cell are all significantly increased.

[0101] Furthermore, when aniline hypophosphite is dissolved in a solvent, aniline hypophosphite inhibits Sn... 2+Oxidizes and passivates uncoordinated Sn in perovskite 2+ While addressing the defects, it does not affect the spreadability of the perovskite solution on the substrate (specifically, the electron transport layer or hole transport layer in application), nor does it inhibit the spread of the thin film on the surface of the tin-based perovskite material. This ensures that the addition of aniline hypophosphite does not negatively affect the functional layers on both sides of the perovskite thin film, and ensures that the prepared tin-based perovskite solar cell has high open-circuit voltage, current density, fill factor, and photoelectric conversion efficiency.

[0102] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A tin-based perovskite material, characterized in that: The tin-based perovskite material consists of a lead-free tin-based perovskite precursor solution and aniline hypophosphite additives; wherein, the aniline hypophosphite additives account for 0.04% to 0.12% of the tin-based perovskite material by mass.

2. The tin-based perovskite material according to claim 1, characterized in that: The aniline hypophosphite additive is one or more of phenyl hypophosphite, aniline hypophosphite, diamine phenyl hypophosphite, phenyl hypophosphite, aniline hypophosphite, and diamine phenyl hypophosphite.

3. The tin-based perovskite material according to claim 1, characterized in that: The lead-free tin-based perovskite precursor solution contains a metal halide and an organic salt. The metal halide is SnX2 and SnF2, and the organic salt is AX. Wherein, A is CH3NH2, and X is one or more of I, Br, and Cl. The halogens in the metal halide and the organic salt may be the same or different.

4. A tin-based perovskite material according to claim 1, characterized in that: By mixing the lead-free tin-based perovskite precursor solution and the solution containing aniline hypophosphite additives in the above proportions, tin-based perovskite material can be obtained.

5. The tin-based perovskite material according to claim 4, characterized in that: The lead-free tin-based perovskite precursor solution is obtained by mixing lead-free tin-based perovskite precursor with a mixed solution. The final concentration of lead-free tin-based perovskite precursor in the solution is 0.9~1.5 mol / L. The mixed solution consists of DMF and DMSO. The volume ratio of DMF to DMSO is (8~9):(2~1).

6. An application of the tin-based perovskite material according to claim 1, characterized in that: Applications of the material in the field of solar cells.

7. A photovoltaic cell device, wherein the cell device comprises, in sequence, a substrate, a hole extraction layer, a tin-based perovskite active layer, an electron extraction layer, and a metal electrode layer, characterized in that: The battery device contains a tin-based perovskite active layer formed from the tin-based perovskite material as described in claim 1.

8. The photovoltaic cell according to claim 7, characterized in that: The tin-based perovskite active layer is formed by coating the tin-based perovskite material of claim 1 onto the surface of the SAM layer and performing a two-step annealing process.

9. The photovoltaic cell according to claim 8, characterized in that: The coating is performed using an anti-solvent-assisted spin coating method. The spin coating is a two-step process: the first step has a speed of 1000 rpm / s, a time of 10 s, and an acceleration of 200~500 rpm / s; the second step has a speed of 5000 rpm / s, a time of 30 s, and an acceleration of 1000~2500 rpm / s. The anti-solvent is applied in the 11th second of the second step. The anti-solvent is chlorobenzene.

10. The photovoltaic cell according to claim 8, characterized in that: The annealing was performed in steps, with annealing temperatures of 60 ℃ and 70 ℃, and corresponding annealing times of 3 min and 10 min, respectively.

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