Method for regulating crystallization of vacuum vapor deposition perovskite material

Abstract

The invention belongs to the field of photoelectric materials, and particularly relates to a vacuum vapor deposition perovskite material crystallization method, which is characterized in that vacuum vapor deposition of a perovskite precursor is carried out step by step, and a specific additive containing amide, amino, carboxyl and other functional groups is introduced in the deposition process to realize dynamic regulation and control of perovskite grain growth. According to the method, the perovskite crystallization kinetic process can be regulated and controlled, so that the crystallization of perovskite is optimized, the quality of the film is improved, the defects of the perovskite film are reduced, and the fluorescence quantum yield is improved.

Description

Technical Field

[0001] The invention belongs to the field of optoelectronic materials, and in particular relates to a method for regulating the crystallization of vacuum vapor deposited perovskite materials. Background Art

[0002] At present, the existing perovskite vacuum vapor deposition process has problems such as poor quality, many defects, and low fluorescence quantum yield of perovskite films due to the rapid crystallization of perovskite during the deposition process and the lack of additive control methods, which cannot fully meet the requirements of high-performance perovskite light-emitting devices. Therefore, in vacuum vapor deposition, how to stably and effectively control the perovskite crystallization process to improve its film quality and optoelectronic performance is still a technical bottleneck. Summary of the invention

[0003] In order to solve the problems of poor crystallization quality, many defects and low fluorescence quantum yield of perovskite thin films in the prior art, the present invention mainly provides a method for regulating the crystallization of vacuum vapor deposited perovskite materials: A method for regulating the crystallization of vacuum vapor deposited perovskite materials comprises the following steps: on a substrate deposited with a functional layer, simultaneously or sequentially vacuum vapor depositing a perovskite precursor A and an additive, then vacuum vapor depositing a perovskite precursor B, and then annealing them together.

[0004] Further, the method comprises the following steps: vacuum vapor deposition of precursor A, additives and precursor B on the substrate on which the functional layer is deposited, and then annealing the precursors together. Vacuum vapor deposition may be thermal evaporation, electron beam evaporation, sputtering, and the like.

[0005] Furthermore, the additive is a compound containing functional groups such as amide, amino, carboxyl, phosphorus-oxygen double bond, sulfur-oxygen double bond, carbon-nitrogen double bond, pyrimidine or pyridine, which have strong interactions with the perovskite precursor components.

[0006] Furthermore, the additive is one of pyridine-2,6-dicarboxamide, 5-aminopentanoic acid, 2-pyridinecarboxamide, phthalimide, fumaramide, succinamide, p-hydroxybenzenesulfonamide, diphenylphosphamide, and 3-[2-(2-aminoethoxy)ethoxy]-propionic acid.

[0007] Furthermore, the perovskite precursor A or B is one or more of formamidine hydrohalide, methylamine hydrohalide, cesium halide, or one or more of lead halide.

[0008] Furthermore, the rate of vacuum vapor deposition of precursor A or precursor B is 0.04~1 nm / s; the rate of vacuum vapor deposition of additive is 0.01~1 nm / s.

[0009] Furthermore, the thicknesses of the perovskite precursor A, precursor B and additives are 5 to 200 nm, respectively.

[0010] Furthermore, the thickness of the perovskite precursor A and the precursor B is 20-60 nm; the thickness of the additive is 5-25 nm.

[0011] A vacuum vapor deposited perovskite material prepared by the above method.

[0012] An application of the above-mentioned vacuum vapor deposited perovskite material in the preparation of a light-emitting device, wherein the external quantum efficiency of the light-emitting device is not less than 20%.

[0013] By adopting the above scheme, the method of the present invention has the following advantages: The present invention optimizes the crystallization process of the perovskite film during the deposition process by combining a sequential deposition with an additive control method, thereby solving the problems of poor crystallization quality, many defects and low fluorescence quantum yield of the perovskite film in the prior art.

[0014] The present invention divides the perovskite precursor into multiple stages and sequentially vapor deposits them, respectively completing the deposition of A-site cations and B-site metal ions, accurately controlling the thickness and component ratio of each layer, and introducing specific additives (molecules containing amide functional groups, amino or carboxyl functional groups) between the layers to control the perovskite crystallization kinetics, thereby optimizing the crystallization of the perovskite, thereby improving the quality of the film, reducing the defects of the perovskite film and improving the fluorescence quantum yield.

[0015] By utilizing the chemical regulation effect of additives and combining it with the step-by-step deposition process, we can not only ensure the precise control of the precursor components, but also further regulate the directionality and uniformity of grain growth; the synergistic effect significantly optimizes the optoelectronic properties of the film (such as defect state density, fluorescence intensity, carrier lifetime, etc.).

[0016] The present invention utilizes a method combining sequential deposition with additives to effectively adjust the crystallization rate of perovskite during the deposition process, delay the crystallization of the perovskite film, and obtain a perovskite film with low defect density and high quality. The fluorescence quantum yield of the vacuum vapor-deposited perovskite film can be greater than 80%, and the external quantum efficiency of the light-emitting device prepared based on the vacuum vapor-deposited perovskite can exceed 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the time-resolved photoluminescence spectrum of the perovskite film of Examples 1 and 2 and Comparative Example 1.

[0018] Figure 2 1 is a curve showing the change of fluorescence quantum yield of the perovskite films of Examples 1 and 2 and Comparative Example 1 under different excitation light intensities.

[0019] Figure 3 It is a comparison chart of the electron luminescence quantum yield of the perovskite films of Examples 1 and 2 and Comparative Example 1.

[0020] Figure 4 This is the device external quantum efficiency distribution diagram of Example 2.

[0021] Figure 5 This is a physical diagram of Example 2 of the present invention.

[0022] Figure 6 It is a schematic diagram of the evaporation process of the present invention. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1: (1) Cleaning the substrate before evaporation: ultrasonically clean the substrate with deionized water and ethanol for 20 minutes respectively, and then remove the moisture and solvent on the surface of the substrate; then treat the treated substrate with ultraviolet ozone for 20 minutes.

[0025] (2) Sequential evaporation: Evacuate the vacuum chamber to a vacuum degree of less than 10 -4 Pa, evaporation can begin. The first step is to evaporate the precursor A, formamidine hydroiodide (FAI), and control the evaporation rate to 0.04~0.05 nm / s, with a film thickness of 20~30 nm; the second step is to evaporate the additive 5-aminovaleric acid (5AVA), and control the evaporation rate to 0.01~0.02 nm / s, with a film thickness of 5~10 nm; the third step is to evaporate PbI as precursor B 2 , control the evaporation rate to 0.04~0.06 nm / s and the film thickness to 10~20 nm.

[0026] (3) Post-treatment: The film after evaporation was annealed in a nitrogen atmosphere at a temperature of 100 °C for 10 minutes. The obtained sample was labeled 5AVA.

[0027] Example 2: (1) Cleaning the substrate before evaporation: ultrasonically clean the substrate with deionized water and ethanol for 20 minutes respectively to remove the moisture and solvent on the surface of the substrate; then treat the treated substrate with ultraviolet ozone for 20 minutes.

[0028] (2) Sequential evaporation: Evacuate the vacuum chamber to a vacuum degree of less than 10 -4Pa, evaporation can begin. The first step is to evaporate the precursor A, formamidine hydroiodide, and control the evaporation rate to 0.04~0.05 nm / s, with a film thickness of 20~30 nm; the second step is to evaporate the additive pyridine-2,6-dicarboxamide (PyDA), and control the evaporation rate to 0.01~0.02 nm / s, with a film thickness of 5~10nm; the third step is to evaporate PbI as the precursor B 2 , control the evaporation rate to 0.04~0.06 nm / s and the film thickness to 10~20 nm.

[0029] (3) Post-treatment: The film after evaporation was annealed in a nitrogen atmosphere at a temperature of 100 °C for 10 minutes. The obtained sample was labeled as PyDA.

[0030] Example 3: (1) Cleaning the substrate before evaporation: ultrasonically clean the substrate with deionized water and ethanol for 20 minutes respectively to remove the moisture and solvent on the surface of the substrate; then treat the treated substrate with ultraviolet ozone for 20 minutes.

[0031] (2) Sequential evaporation: Evacuate the vacuum chamber to a vacuum degree of less than 10 -4 Pa, evaporation can begin. The first step is to evaporate the precursor A, methyl ammonium iodide (MAI), and control the evaporation rate to 0.04~0.05 nm / s, with a film thickness of 20~30nm; the second step is to evaporate the additive 5-aminovaleric acid, and control the evaporation rate to 0.01~0.02 nm / s, with a film thickness of 5~10 nm; the third step is to evaporate PbI as the precursor B 2 , control the evaporation rate to 0.04~0.06 nm / s and the film thickness to 10~20 nm.

[0032] (3) Post-treatment: The film after evaporation was annealed in a nitrogen atmosphere at a temperature of 100 °C for 10 min.

[0033] Example 4: (1) Cleaning the substrate before evaporation: ultrasonically clean the substrate with deionized water and ethanol for 20 minutes respectively to remove the moisture and solvent on the surface of the substrate; then treat the treated substrate with UV ozone for 20 minutes.

[0034] (2) Sequential evaporation: Evacuate the vacuum chamber to a vacuum degree of less than 10 -4 Pa, evaporation can begin. The first step is to evaporate the precursor A, methyl iodide ammonium, and control the evaporation rate to 0.04~0.05 nm / s, with a film thickness of 20~30nm; the second step is to evaporate the additive pyridine-2,6-dicarboxamide, and control the evaporation rate to 0.01~0.02 nm / s, with a film thickness of 5~10nm; the third step is to evaporate PbI as the precursor B 2, control the evaporation rate to 0.04~0.06 nm / s and the film thickness to 10~20 nm.

[0035] (3) Post-treatment: The film after evaporation was annealed in a nitrogen atmosphere at a temperature of 100 °C for 10 min.

[0036] Example 5: (1) Cleaning the substrate before evaporation: ultrasonically clean the substrate with deionized water and ethanol for 20 minutes respectively to remove the moisture and solvent on the surface of the substrate; then treat the treated substrate with UV ozone for 20 minutes.

[0037] (2) Reference Figure 3 Sequential evaporation: evacuate the vacuum chamber to a vacuum degree of less than 10 -4 The first step is to evaporate the precursor A, formamidine hydroiodide, and control the evaporation rate to 0.04-0.05 nm / s, with a film thickness of 20-30 nm; the second step is to evaporate the additive diphenylphosphine amide, and control the evaporation rate to 0.01-0.02 nm / s, with a film thickness of 5-10 nm; the third step is to evaporate PbI as the precursor B. 2 , control the evaporation rate to 0.04~0.06 nm / s and the film thickness to 10~20 nm.

[0038] (3) Post-treatment: The film after evaporation was annealed in a nitrogen atmosphere at a temperature of 100 °C for 10 min.

[0039] Example 6: (1) Cleaning the substrate before evaporation: ultrasonically clean the substrate with deionized water and ethanol for 20 minutes respectively to remove the moisture and solvent on the surface of the substrate; then treat the treated substrate with UV ozone for 20 minutes.

[0040] (2) Sequential evaporation: Evacuate the vacuum chamber to a vacuum degree of less than 10 -4 Pa, evaporation can begin. In the first step, the precursor A, formamidine hydroiodide, and the additive 5-aminovaleric acid are simultaneously evaporated, the evaporation rate is controlled to be 0.04-0.05 nm / s, and the film thickness is 25-35 nm; the second step is to evaporate PbI as the precursor B. 2 , control the evaporation rate to 0.04~0.06 nm / s and the film thickness to 10~20 nm.

[0041] (3) Post-treatment: The film after evaporation was annealed in a nitrogen atmosphere at a temperature of 100°C for 10 minutes.

[0042] Comparative Example: (1) Cleaning the substrate before evaporation: ultrasonically clean the substrate with deionized water and ethanol for 20 minutes respectively, and then remove the moisture and solvent on the surface of the substrate; then treat the treated substrate with UV ozone for 20 minutes.

[0043] (2) Sequential evaporation: Evacuate the vacuum chamber to a vacuum degree of less than 10 -4 The first step is to evaporate the precursor A, formamidine hydroiodide, with a controlled evaporation rate of 0.04-0.05 nm / s and a film thickness of 20-30 nm; the second step is to evaporate PbI as the precursor B. 2 , control the evaporation rate to 0.04~0.06 nm / s and the film thickness to 10~20 nm.

[0044] (3) Post-treatment: The film after evaporation was annealed in a nitrogen atmosphere at a temperature of 100 °C for 10 minutes. The obtained sample was marked as additive-free.

[0045] Example sample test: In order to confirm the effect of the method and additives of the present invention on carrier transport and lifetime in perovskite thin films, time-resolved photoluminescence spectroscopy tests were performed on samples of Examples 1, 2 and the comparative example. The results are as follows: Figure 1 As shown in the figure, it can be seen that the method of the present invention can effectively reduce the defects inside the perovskite material and improve the crystallization quality of the perovskite film. The performance of the material in Example 2 using pyridine-2,6-dicarboxamide is better than that of Example 1 using 5-aminovaleric acid, indicating that the selection of additives has a great influence on the improvement of material performance.

[0046] In order to evaluate the effect of the method of the present invention on the photoluminescence efficiency of the material, the fluorescence quantum yield of the samples of Examples 1, 2 and the comparative example under different excitation light intensities was tested. Figure 2 As shown in the figure, compared with the comparative example without evaporation of additives, the materials prepared by the method of the present invention have extremely high fluorescence quantum yields. The fluorescence quantum yield of the comparative example is less than 10%, while the fluorescence quantum yield of the material of the present invention is close to 40%, and the yield of Example 2 even reaches more than 80%, which is much higher than the comparative example, indicating that the method of the present invention can significantly improve the luminescence potential of the material.

[0047] The electron luminescence quantum yield of the samples of Examples 1, 2 and the comparative example was tested. Figure 3 As shown. Compared with the comparative example without evaporation of additives, the light-emitting diodes with perovskite as the light-emitting layer prepared by the method of the present invention all show higher electroluminescent external quantum efficiency. The electroluminescent external quantum efficiency of the comparative example is less than 4%, while the electroluminescent external quantum efficiency of the device with the perovskite light-emitting layer prepared by the method of the present invention is greater than 10%, and the yield of Example 2 even reaches more than 20%, which is much higher than the comparative example. Figure 4 It can be seen that the perovskite material prepared by the method of the present invention exhibits good uniformity, and Figure 5The large-size sample photos show that the present invention is compatible with the preparation of large-area light-emitting devices.

[0048] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A method for regulating the crystallization of vacuum vapor deposited perovskite materials, characterized in that: The following steps are involved: On a substrate with a functional layer deposited thereon, a perovskite precursor A and an additive are simultaneously or sequentially vacuum vapor deposited, and then a perovskite precursor B is vacuum vapor deposited, and then annealed together.

2. The method for regulating the crystallization of vacuum vapor deposited perovskite materials according to claim 1, characterized in that: The following steps are involved: Precursor A, additives and precursor B are sequentially deposited by vacuum vapor deposition on the substrate with the functional layer, and then annealed together.

3. The method for regulating the crystallization of vacuum vapor deposited perovskite material according to claim 1 or 2, characterized in that: The additive is a compound containing an amide, an amino group, a carboxyl group, a phosphorus-oxygen double bond, a sulfur-oxygen double bond, a carbon-nitrogen double bond, a pyrimidine or a pyridine functional group.

4. The method for regulating the crystallization of vacuum vapor deposited perovskite material according to claim 1 or 2, characterized in that: The additive is one of pyridine-2,6-dicarboxamide, 5-aminopentanoic acid, 2-pyridinecarboxamide, phthalimide, fumaramide, succinamide, p-hydroxybenzenesulfonamide, diphenylphosphamide, and 3-[2-(2-aminoethoxy)ethoxy]-propionic acid.

5. The method for regulating the crystallization of vacuum vapor deposited perovskite material according to claim 1 or 2, characterized in that: The perovskite precursor A or B is one or more of formamidine hydrohalide, methylamine hydrohalide, cesium halide, or one or more of lead halide and tin halide.

6. The method for regulating the crystallization of vacuum vapor deposited perovskite material according to claim 1 or 2, characterized in that: The rate of vacuum vapor deposition of precursor A or precursor B is 0.04~1 nm / s; the rate of vacuum vapor deposition of additives is 0.01~1 nm / s.

7. The method for regulating the crystallization of vacuum vapor deposited perovskite material according to claim 1 or 2, characterized in that: The thickness of the perovskite precursor A, precursor B and additives are 5-200 nm respectively.

8. The method for regulating the crystallization of vacuum vapor deposited perovskite material according to claim 1 or 2, characterized in that: The thickness of the perovskite precursor A and precursor B is 20-60 nm; the thickness of the additive is 5-25 nm.

9. A vacuum vapor deposited perovskite material prepared by the method according to claim 1 or 2.

10. Use of the vacuum vapor deposited perovskite material according to claim 9 in preparing a light-emitting device, characterized in that: The external quantum efficiency of the light-emitting device shall not be less than 20%.

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