ABX3 type perovskite material stabilized by liquid crystal material and preparation method of ABX3 type perovskite material

Abstract

The invention discloses an ABX3 type perovskite material stabilized by a liquid crystal material and a preparation method of the ABX3 type perovskite material, and belongs to the field of semiconductor photoelectric materials and energy materials. The preparation method comprises the following steps: (1) uniformly mixing lead iodide and dodecyl dimethyl benzyl ammonium bromide, and carrying out heat treatment reaction to obtain a liquid crystal material solid; (2) dissolving the obtained liquid crystal material solid in an organic solvent to obtain a precursor solution; and (3) coating the surface of the ABX3 type perovskite thin film with the obtained precursor solution to obtain the ABX3 type perovskite material stabilized by the liquid crystal material. The ABX3 type perovskite which is high in quality and ultrahigh in stability is prepared through the method, the stability and the photoelectric property of the perovskite material are improved in order of magnitude, and the ABX3 type perovskite can be widely applied to the photoelectric fields of batteries, light emitting, detectors and the like; the preparation method has the characteristics of simplicity, easiness in control, convenience in operation, lower cost and the like, and is convenient for large-scale production in factories.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of semiconductor photoelectric materials and energy materials, and particularly relates to an ABX3 type perovskite material stabilized by a liquid crystal material and a preparation method thereof. BACKGROUND

[0002] Perovskite materials refer to materials having the same crystal structure as calcium titanate (CaTiO3) in a broad sense, and the general structure formula thereof is ABX3, wherein A represents inorganic or organic cations such as methylammonium (MA + , CH3NH3 + ), formamidinium (FA + , CH2(NH2)2 + ), cesium (Cs + ), rubidium (Rb + ) and the like; B represents divalent metal ions such as lead (Pb 2+ ), tin (Sn 2+ ), germanium (Ge 2+ ) and the like; and X represents halide anions or pseudo-halide anions, including chloride (Cl - ), bromide (Br - ), iodide (I - ), thiocyanate (SCN - ) and the like.

[0003] Perovskite materials, especially metal halide perovskite materials, have very excellent photoelectric properties and are suitable for use as active layer materials. Since 2009, ABX3 type metal halide perovskite has been widely used in the fields of photoelectricity such as solar cells, light-emitting, and detectors due to high carrier mobility, high light absorption coefficient and adjustable band gap. However, the stability of this type of perovskite material, especially the phase stability, has become a major bottleneck for the industrialization of perovskite optoelectronic devices. Due to the inherent volatility of the A-site cations, perovskite is prone to phase transition or decomposition under working conditions, which greatly limits the working stability of perovskite optoelectronic devices.

[0004] The component regulation strategy of perovskite thin films has been developed to stabilize the organic components and octahedral twist in perovskite, so as to improve the overall stability of the material. For example, completely removing methylamine ions in the perovskite thin film and replacing them with formamidinium ions with better stability can significantly improve the stability of the perovskite thin film (Wang, H. et al. 2015, Adv. Energy Mater :1501310). Or increasing the content of inorganic cesium ions in the perovskite thin film to inhibit the volatilization of cations (Wang, H. et al. 2015, 5 :1501310). Or increasing the content of inorganic cesium ions in the perovskite thin film to inhibit the volatilization of cations (Wang, H. et al. 2015, ACS EnergyLett. 2021, 6: 2735−2741). But the high ratio of formamidinium ion or cesium ion in these strategies will lead to the tolerance factor of the obtained perovskite deviating from the optimal range, making the thin film prone to phase transition.

[0005] Perovskite thin film surface treatment is an effective strategy to improve the phase stability of perovskite thin films. For example, YOO et al. formed a low-dimensional perovskite on the surface of perovskite using different carbon chain length ammonium salts, which significantly improved the phase stability of perovskite thin films (Yoo, K. et al. 2019, 12: 2192). And Jiang et al. introduced phenethylammonium iodide on the surface of perovskite, which not only reduced the loss of interfacial recombination, but also improved the thermal stability of perovskite thin films (Jiang, Y. et al. 2019, 13, 460). But the low-dimensional perovskite or the foreign molecules introduced in these strategies and the original perovskite may have different thermal expansion coefficients and lattice mismatch, which may lead to new stability challenges. Energy Environ. Sci. Nature Photonics

[0006] Therefore, solving the key scientific problem of poor perovskite stability is crucial to promote the industrial process of perovskite optoelectronic devices (solar cells, photodetectors, and light-emitting diodes, etc.). SUMMARY

[0007] The purpose of the present application is to provide a brand new perovskite material stabilization method, which stabilizes the perovskite components by depositing liquid crystal materials on the surface of perovskite, and finally obtains high-quality perovskite thin films with ultra-high stability.

[0008] To achieve the above purpose, the technical scheme adopted by the present application is as follows: The present application provides a preparation method of ABX3 type perovskite material stabilized by liquid crystal material, comprising the following steps: (1) uniformly mix lead iodide and dodecyl dimethyl benzyl ammonium bromide (DDBAB), and obtain a liquid crystal material solid after heat treatment reaction; (2) dissolve the liquid crystal material solid obtained in step (1) in an organic solvent to obtain a precursor solution; (3) coat the precursor solution obtained in step (2) on the surface of ABX3 type perovskite thin film to obtain ABX3 type perovskite material stabilized by liquid crystal material.

[0009] The present application utilizes the solid phase reaction of lead iodide and dodecyl dimethyl benzyl ammonium bromide powder to synthesize liquid crystal material, and then spin-coats the solution thereof on the surface of ABX3 type perovskite thin film to stabilize the perovskite thin film components. Research shows that after introducing liquid crystal material on the surface of perovskite, the perovskite crystal phase with high purity is still maintained after 1000 hours of 100℃ heating treatment.

[0010] ​​Preferably, in step (1), the lead iodide and dodecyl dimethyl benzyl ammonium bromide powder are weighed according to the molar ratio, put into a mortar and ground thoroughly; The molar ratio of the lead iodide to the dodecyl dimethyl benzyl ammonium bromide powder is 1: (1-3).

[0011] In the embodiments of the present application, as an example, the molar ratio of the lead iodide to the dodecyl dimethyl benzyl ammonium bromide powder is 1:2 and 1:3, both of which can obtain high-quality and ultra-high-stability perovskite thin film materials, and in particular, when the molar ratio is 1:2, the perovskite thin film obtained still maintains a high-purity perovskite crystal phase after aging for 1000 hours at 100°C.

[0012] In some embodiments of the present application, the temperature of the heat treatment reaction is 100-170°C.

[0013] Preferably, in step (2), the organic solvent is at least one of chlorobenzene and toluene; more preferably, the organic solvent is chlorobenzene. The concentration of the precursor solution is 0.5-10 mg / mL.

[0014] Specifically, in step (3), the preparation method of the ABX3 type perovskite thin film comprises: mixing the halide salt AX, the halide metal salt BX2 and the additive in an organic solvent to obtain a perovskite precursor solution; and coating the perovskite precursor solution on a substrate to obtain an ABX3 type perovskite thin film. Wherein A in the halide salt AX is an inorganic and / or organic cation; B in the halide metal BX2 represents a divalent metal ion; and X represents a halide anion.

[0015] Preferably, A in the halide salt AX can be, but is not limited to, at least one of MA + , FA + , Cs + and Rb + ; B in the halide metal BX2 is at least one of Pb 2+ , Sn 2+ and Cd 2+ ; X is at least one of I - , Br - and Cl - .

[0016] More preferably, the halide salt AX is composed of cesium iodide and formamidinium iodide; The halide metal BX2 is lead iodide; The molar ratio of the halide salt AX to the halide metal BX2 is 1:1.

[0017] Preferably, in step (3), the additive for inducing perovskite film formation is at least one of dimethylamine hydroiodide (DMAI), methylamine chloride (MACl), and formamidine chloride (FACl); and the molar ratio of the additive to the halide AX is 0.18-1:1. The solvent is at least one of N,N-dimethylformamide and dimethyl sulfoxide.

[0018] Preferably, in step (3), the perovskite precursor solution is coated on the substrate and then annealed, and the ABX3 perovskite film is obtained after annealing. The annealing temperature is 100-170 DEG C, and the annealing time is 10-50 min. The thickness of the ABX3 perovskite film is 300 nm-1000 nm.

[0019] Specifically, the perovskite precursor solution can be 0.7-2.0 mol / L, and is spin-coated on the substrate at 5000 rpm for 30 s. The substrate can be, but is not limited to, an FTO substrate (Fluorine-doped Tin Oxide conductive glass substrate).

[0020] Further, in step (3), the precursor solution obtained in step (2) is coated on the surface of the ABX3 perovskite film, and the solvent in the precursor solution is removed by heating. The heating temperature is 100-180 DEG C, and the heating time is 2-10 min.

[0021] The method for coating the precursor solution obtained in step (2) on the surface of the ABX3 perovskite film can be a solution spin coating method, and can also be hot stamping, thermal evaporation, etc.

[0022] The application also provides an ABX3 perovskite material stabilized by the liquid crystal material, which is prepared by the above preparation method.

[0023] The perovskite film crystal crystallinity is improved after the liquid crystal material is introduced on the surface. Compared with the conventional perovskite material, the material stability is greatly improved, and the performance of the perovskite film itself is maintained.

[0024] The application has the following beneficial effects: (1) The application realizes the order of magnitude improvement of the perovskite material stability and photoelectric performance by respectively preparing a liquid crystal material and a perovskite film, and then spin-coating the liquid crystal material solution on the perovskite film to obtain a dense perovskite film on the surface.

[0025] (2) The method for introducing liquid crystal material to the surface of perovskite crystal material is realized by a solution spin coating method, which reduces the requirements for production facilities. The preparation method has the characteristics of simple control, convenient operation, low cost and the like, and meets the needs of large-scale industrial production.

[0026] (3) The ABX3 type perovskite prepared by the method has high quality and super-high stability, and can be widely applied to the fields of photoelectricity such as batteries, light emission and detectors. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 Differential scanning calorimetry spectrum of the liquid crystal material obtained when the molar ratio of lead iodide to dodecyl dimethyl benzyl ammonium bromide is 1:2 in Example 1.

[0028] Figure 2 Scanning electron microscope photograph of the perovskite thin film obtained in Example 1.

[0029] Figure 3 Ultraviolet-visible absorption spectrum of the perovskite thin film obtained in Example 1.

[0030] Figure 4 X-ray diffraction spectrum of the liquid crystal material obtained in Example 1 after treatment.

[0031] Figure 5 X-ray diffraction spectrum of the perovskite thin film obtained in Example 1 after aging for 1000 hours at 100°C.

[0032] Figure 6 Scanning electron microscope photograph of the perovskite thin film obtained in Comparative Example 1.

[0033] Figure 7 Original X-ray diffraction spectrum of the perovskite thin film before aging in Comparative Example 1.

[0034] Figure 8 X-ray diffraction spectrum of the perovskite thin film obtained in Comparative Example 1 after aging for 200 hours at 100°C.

[0035] Figure 9 X-ray diffraction spectrum of the perovskite thin film obtained in Example 2.

[0036] Figure 10 X-ray diffraction spectrum of the perovskite thin film obtained in Example 3.

[0037] Figure 11 X-ray diffraction spectrum of the perovskite thin film obtained in Example 4 after aging for 200 hours at 100°C. DETAILED DESCRIPTION

[0038] The application will be further described in connection with the following specific examples. The following examples are only used to illustrate the application, and are not used to limit the application. Any modification or replacement of the method, step or condition of the application without departing from the spirit and essence of the application shall fall within the scope of the application.

[0039] The test methods used in the following examples are conventional methods unless otherwise specified; the materials, reagents, etc. used are commercially available reagents and materials unless otherwise specified.

[0040] Example 1 In this example, the liquid crystal material is deposited on the surface of the Cs 0.7 FA 0.3 PbI3crystal material, thereby obtaining a high-stability Cs 0.7 FA 0.3 perovskite material containing the liquid crystal material.

[0041] 1. Material preparation 1) 460 mg of lead iodide and 768 mg of dodecyl dimethyl benzyl ammonium bromide powder were ground in a mortar to mix them thoroughly; then the mixed powder was moved into a beaker and heated at 150°C for 1 h to make them react thoroughly, thereby obtaining a liquid crystal material.

[0042] 2) The liquid crystal material of step 1) with a molar ratio of lead iodide to dodecyl dimethyl benzyl ammonium bromide of 1:2 was dissolved in chlorobenzene to prepare a 2 mg mL -1 solution C.

[0043] 3) 461 mg of lead iodide, 181.87 mg of cesium iodide, 51.59 mg of formamidinium iodide and 173 mg of methylamine hydroiodide were dissolved in 1429 μL of DMF solvent to obtain a precursor solution A; the above-mentioned lead iodide, cesium iodide, formamidinium iodide and methylamine hydroiodide were calculated according to a molar ratio of 1:0.7:0.3:1.

[0044] 4) The solution A obtained in step 3) was spin-coated onto an FTO substrate at 3000 rpm for 30 s, and the spin-coated substrate was annealed at 170°C for 45 min to obtain a perovskite film B.

[0045] 5) The chlorobenzene solution C obtained in step 2) was spin-coated above the perovskite film B at 3000 rpm for 30 s, and then heated at 100°C for 10 min, thereby obtaining a perovskite material containing the liquid crystal material on the surface.

[0046] 2. Performance characterization Figure 1The differential scanning calorimetry spectrum of the liquid crystal material shows that the liquid crystal material has multiple phase transition points when changing from a liquid to a solid, which is a characteristic of a liquid crystal.

[0047] Figure 2 The scanning electron microscope image of the perovskite film surface prepared in Example 1 shows that the perovskite film surface after introducing the liquid crystal material is dense and has a high coverage.

[0048] Figure 3 The ultraviolet-visible light spectrum of the product prepared in Example 1 shows that the perovskite film obtained in Example 1 has a clear characteristic absorption, and the absorption edge is 746 nm.

[0049] Figure 4 The X-ray diffraction spectrum of the Cs 0.7 FA 0.3 The X-ray diffraction spectrum of the PbI3 perovskite film shows that the perovskite has good crystallinity.

[0050] Figure 5 The X-ray diffraction spectrum of the perovskite film obtained in Example 1 after aging at 100°C for 1000 hours shows that the perovskite film after 1000 hours of aging still maintains a high-purity perovskite crystal phase.

[0051] Comparative Example 1 The method of this comparative example is the same as that of Example 1, except that no liquid crystal material is synthesized and introduced in steps 1), 2), and 5), i.e., a perovskite film is directly obtained.

[0052] Figure 6 The scanning electron microscope image of the material obtained in Comparative Example 1 shows that there are no longitudinal through grains in the film.

[0053] Figure 7 The original X-ray diffraction spectrum of the perovskite film before aging in Comparative Example 1 shows that the Cs 0.7 FA 0.3 The PbI3 perovskite film has good crystallinity.

[0054] Figure 8 The X-ray diffraction spectrum of the perovskite film obtained in Comparative Example 1 after aging at 100°C for 200 hours shows that the yellow phase of the perovskite film after 200 hours of aging is significantly enhanced.

[0055] Example 2 In this example, a liquid crystal material is introduced into a CsPbI3 crystal material, thereby obtaining a stable perovskite material containing a liquid crystal material and having high stability.

[0056] 1. Material preparation The method is the same as that in Example 1, except that the perovskite formula in step 3) is adjusted as follows: 461 mg of lead iodide, 259.81 mg of cesium iodide, and 173 mg of dimethylamine hydroiodide are dissolved in 1429 μL of DMF solvent to obtain precursor solution A; the above-mentioned lead iodide, cesium iodide, and dimethylamine hydroiodide are calculated as 1:1:1 in terms of molar ratio.

[0057] 2. Performance characterization Figure 9 The X-ray diffraction pattern of the product prepared in Example 2 is good in perovskite crystallinity after introducing the liquid crystal material at the surface.

[0058] As can be seen, the perovskite thin film material of high quality and ultra-high stability is still obtained in this embodiment.

[0059] Example 3 In this embodiment, the liquid crystal material is introduced into FA 0.95 Cs 0.05 PbI3 crystal material, so as to obtain high-stability FA 0.95 Cs 0.05 PbI3 perovskite material containing the liquid crystal material.

[0060] 1. Material preparation The method is the same as that in Example 1, except that the perovskite formula used in step 3) is adjusted as follows: 750 mg of lead iodide, 21.1 mg of cesium iodide, and 266 mg of formamidinium iodide are dissolved in 900 μL of DMF and 100 μL of DMSO solvent to obtain a precursor solution and 20 mg of methylamine chloride is added; the above-mentioned lead iodide, cesium iodide, formamidinium iodide, and methylamine chloride are calculated as 1:0.05:0.95:0.18 in terms of molar ratio.

[0061] 2. Performance characterization Figure 10 The X-ray diffraction pattern of Example 3 is good in perovskite crystallinity after introducing the liquid crystal material at the surface.

[0062] As can be seen, the perovskite thin film material of high quality and ultra-high stability is still obtained in this embodiment.

[0063] Example 4 In this embodiment, the liquid crystal material obtained when the molar ratio of lead iodide to dodecyl dimethyl benzyl ammonium bromide is 1:3 is introduced into Cs 0.7 FA 0.3 PbI3 crystal material, so as to obtain high-stability Cs 0.7 FA 0.3 PbI3 perovskite material containing the liquid crystal material.

[0064] 1. Material preparation The method is the same as that in Example 1, except that the liquid crystal material formulation used in step 1) is adjusted as follows: 460 mg of lead iodide is ground with 1152 mg of dodecyl dimethyl benzyl ammonium bromide powder in a mortar to mix them thoroughly, to obtain a liquid crystal material reactant.

[0065] 2. Performance characterization Figure 11 The X-ray diffraction pattern of the perovskite thin film obtained in Example 4 after aging for 200 hours at 100°C shows that the perovskite thin film after aging for 200 hours still maintains a high-purity perovskite crystal phase.

[0066] It can be seen that the perovskite thin film material obtained in this example still has high quality and ultra-high stability.

[0067] The above-described examples are only preferred schemes of the present application and are not intended to limit the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, all technical schemes obtained by equivalent replacement or equivalent transformation fall within the protection scope of the present application.

Claims

1. A method for preparing ABX3-type perovskite material stabilized by liquid crystal materials, characterized in that, Includes the following steps: (1) Lead iodide and dodecyl dimethyl benzyl ammonium bromide are mixed evenly and then heat-treated to obtain a solid liquid crystal material; (2) Dissolve the solid liquid crystal material obtained in step (1) in an organic solvent to obtain a precursor solution; (3) The precursor solution obtained in step (2) is coated on the surface of the ABX3 perovskite film to obtain the ABX3 perovskite material stabilized by the liquid crystal material.

2. The method for preparing ABX3-type perovskite material stabilized by liquid crystal material as described in claim 1, characterized in that, In step (1), lead iodide and dodecyl dimethyl benzyl ammonium bromide powders are weighed according to the molar ratio and ground thoroughly in a mortar; The molar ratio of lead iodide to dodecyl dimethyl benzyl ammonium bromide powder is 1:1-3; The temperature of the heat treatment reaction is 100~170℃.

3. The method for preparing ABX3-type perovskite material stabilized by liquid crystal material as described in claim 1, characterized in that, In step (2), the organic solvent is at least one of chlorobenzene and toluene; The concentration of the precursor solution is 0.5~10 mg / mL.

4. The method for preparing ABX3-type perovskite material stabilized by liquid crystal material as described in claim 1, characterized in that, In step (3), the preparation method of the ABX3 type perovskite thin film includes: A perovskite precursor solution was obtained by mixing and dissolving a halide salt AX, a metal halide salt BX2, and an additive in an organic solvent; the perovskite precursor solution was then coated onto a substrate to obtain an ABX3 type perovskite film. In the halide salt AX, A represents an inorganic and / or organic cation; in the halide metal BX2, B represents a divalent metal ion; and X represents a halide anion.

5. The method for preparing ABX3-type perovskite material stabilized by liquid crystal material as described in claim 4, characterized in that, In the halide salt AX, A is MA. + FA + Cs + and Rb + At least one of them; In metal halide BX2, B is Pb. 2+ Sn 2+ and Cd 2+ At least one of them; X is I - ,Br - and Cl - At least one of them.

6. The method for preparing ABX3-type perovskite material stabilized by liquid crystal material as described in claim 5, characterized in that, The halide salt AX is composed of cesium iodide and formamidine iodide; The halide metal BX2 is lead iodide; The molar ratio of the halide salt AX to the halide metal BX2 is 1:

1.

7. The method for preparing ABX3-type perovskite material stabilized by liquid crystal material as described in claim 4, characterized in that, In step (3), the additive is at least one of dimethylamine hydroiodate, methylamine chloride, and formamidine chloride; the molar ratio of the additive to the halide salt AX is 0.18 to 1:

1. The solvent is at least one of N,N-dimethylformamide and dimethyl sulfoxide.

8. The method for preparing ABX3-type perovskite material stabilized by liquid crystal material as described in claim 4, characterized in that, In step (3), the perovskite precursor solution is coated onto the substrate and then annealed to obtain the ABX3 type perovskite film. The annealing temperature is 100~170℃, and the annealing time is 10~50 min; The thickness of the ABX3 type perovskite film is 300 nm to 1000 nm.

9. The method for preparing ABX3-type perovskite material stabilized by liquid crystal material as described in claim 1, characterized in that, In step (3), the precursor solution obtained in step (2) is coated on the surface of the ABX3 perovskite film, and the solvent in the precursor solution is removed by heating. The heating temperature is 100~180℃, and the time is 2~10 min.

10. An ABX3 type perovskite material stabilized by liquid crystal material prepared by the preparation method according to any one of claims 1-9.

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