Method for regulating crystallization of perovskite material by vacuum vapor deposition

Abstract

The application belongs to the field of photoelectric materials, and particularly relates to a method for vacuum vapor deposition of perovskite material crystallization, step-by-step vacuum vapor deposition of perovskite precursors, and introduction of specific additives containing functional groups such as amide, amino, carboxyl and the like during the deposition process to realize kinetic regulation of perovskite grain growth. The method can regulate the kinetic process of perovskite crystallization, thereby optimizing the crystallization of perovskite, improving the quality of the thin film, reducing the defects of the perovskite thin film and improving the fluorescence quantum yield.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of optoelectronic materials, and particularly relates to a method for regulating and controlling crystallization of perovskite materials in vacuum vapor deposition. BACKGROUND

[0002] At present, the existing perovskite vacuum vapor deposition process cannot completely meet the requirements of high-performance perovskite light-emitting devices due to the problems of fast crystallization of perovskite in the deposition process and lack of additive regulation means, resulting in poor perovskite film quality, many defects, and low fluorescence quantum yield. Therefore, how to stably and effectively regulate and control the perovskite crystallization process to improve the film quality and photoelectric performance is still a technical bottleneck in vacuum vapor deposition. SUMMARY

[0003] To solve the problems of poor perovskite film crystallization quality, many defects, and low fluorescence quantum yield in the prior art, the application mainly provides a method for regulating and controlling crystallization of perovskite materials in vacuum vapor deposition:

[0004] The method for regulating and controlling crystallization of perovskite materials in vacuum vapor deposition comprises the following steps: simultaneously or sequentially vacuum vapor depositing perovskite precursors A and additives on a substrate on which a functional layer is deposited, then vacuum vapor depositing perovskite precursors B, and finally annealing together.

[0005] Further, the method comprises the following steps: sequentially vacuum vapor depositing precursors A, additives, and precursors B on a substrate on which a functional layer is deposited, and then annealing together. The vacuum vapor deposition can be thermal evaporation, electron beam evaporation, sputtering, or the like.

[0006] Further, the additives are compounds 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 interaction with components of perovskite precursors.

[0007] Further, the additives are one of pyridine-2,6-dicarboxamide, 5-aminovaleric acid, 2-picolinamide, phthalimide, fumaramide, suberamide, p-hydroxybenzenesulfonamide, diphenylphosphoramide, and 3-[2-(2-aminoethoxy)ethoxy]-propionic acid.

[0008] Further, the precursors A or B of the perovskite are one or more of formamidinium hydrohalide, methylamine hydrohalide, and cesium halide, or one or more of lead halide.

[0009] Further, the rate of vacuum vapor deposition of the precursors A or B is 0.04-1 nm / s, and the rate of vacuum vapor deposition of the additives is 0.01-1 nm / s.

[0010] Further, thicknesses of the perovskite precursors A and B and the additive are 5-200 nm respectively.

[0011] Further, thicknesses of the perovskite precursors A and B are 20-60 nm; and thickness of the additive is 5-25 nm.

[0012] A vacuum vapor deposition perovskite material prepared by the above method.

[0013] Application of the above vacuum vapor deposition perovskite material in preparation of a light-emitting device, wherein the external quantum efficiency of the light-emitting device is not less than 20%.

[0014] By using the above scheme, the method of the present application has the following advantages:

[0015] The present application optimizes the crystallization process of the perovskite thin film in the deposition process by sequential deposition combined with the regulation of additives, and solves the problems of poor crystallization quality, many defects and low fluorescence quantum yield of the perovskite thin film in the prior art.

[0016] The present application vapor deposits the perovskite precursors in multiple stages in sequence, respectively completes the deposition of A-site cations and B-site metal ions, accurately controls the thickness and component ratio of each layer, introduces specific additives (molecules containing amide, amino or carboxyl functional groups) between the layers to regulate the perovskite crystallization kinetics, thereby optimizing the crystallization of the perovskite, and improving the quality of the thin film, reducing the defects of the perovskite thin film and improving the fluorescence quantum yield.

[0017] By using the chemical regulation effect of the additive combined with the step-by-step deposition process, the accuracy control of the precursor components is ensured, and the directionality and uniformity of the grain growth are further regulated; the synergistic effect significantly optimizes the optoelectronic properties (such as defect state density, fluorescence intensity, carrier lifetime, etc.) of the thin film.

[0018] By using the method of sequential deposition combined with additives, the present application can effectively regulate the crystallization rate of the perovskite in the deposition process, delay the crystallization of the perovskite thin film, obtain a perovskite thin film with low defect density and high quality, the fluorescence quantum yield of the vacuum vapor deposition perovskite thin film can be greater than 80%, and the external quantum efficiency of the light-emitting device prepared based on the vacuum vapor deposition perovskite can exceed 20%. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the time-resolved photoluminescence spectrum of the perovskite thin film of Examples 1, 2 and Comparative Example 1.

[0020] Figure 2 is the fluorescence quantum yield variation curve of the perovskite thin film of Examples 1, 2 and Comparative Example 1 under different excitation light intensities.

[0021] Figure 3 is a comparison chart of the electron luminescence quantum yield of the perovskite thin film of Example 1, 2 and Comparative Example 1.

[0022] Figure 4 is a device external quantum efficiency distribution chart of Example 2.

[0023] Figure 5 is a real object chart of Example 2 of the present application.

[0024] Figure 6 is a schematic diagram of the evaporation process of the present application. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0026] Example 1: (1) Pre-treatment cleaning of the substrate before evaporation: ultrasonic cleaning with deionized water and ethanol for 20 minutes, respectively, and then removing the water and solvent on the surface of the substrate; then, the treated substrate is treated with ultraviolet ozone for 20 minutes.

[0027] (2) Sequential evaporation: the vacuum chamber is evacuated to a vacuum degree less than 10 -4 Pa, and then evaporation can be started. In the first step, the precursor A formamidinium hydriodide (FAI) is evaporated, the evaporation rate is controlled to be 0.04~0.05 nm / s, and the film thickness is 20~30 nm; in the second step, the additive 5-aminovaleric acid (5AVA) is evaporated, the evaporation rate is controlled to be 0.01~0.02 nm / s, and the film thickness is 5~10 nm; in the third step, PbI2 as the precursor B is evaporated, the evaporation rate is controlled to be 0.04~0.06 nm / s, and the film thickness is 10~20 nm.

[0028] (3) Post-treatment: the thin film after evaporation is annealed in a nitrogen atmosphere, the annealing temperature is 100 ℃, and the annealing time is 10 minutes. The obtained sample is marked as 5AVA.

[0029] Example 2: (1) Pre-treatment cleaning of the substrate before evaporation: ultrasonic cleaning with deionized water and ethanol for 20 minutes, respectively, and then removing the water and solvent on the surface of the substrate; then, the treated substrate is treated with ultraviolet ozone for 20 minutes.

[0030] (2) Sequential evaporation: the vacuum chamber is evacuated to a vacuum degree less than 10 -4Evaporation can start at 10 Pa. The first step is to evaporate precursor A methylammonium iodide (MAI) at a rate of 0.04-0.05 nm / s to a thickness of 20-30 nm. The second step is to evaporate additive 5-aminopentanoic acid at a rate of 0.01-0.02 nm / s to a thickness of 5-10 nm. The third step is to evaporate PbI2 as precursor B at a rate of 0.04-0.06 nm / s to a thickness of 10-20 nm.

[0031] (3) Post-processing: anneal the film after evaporation in a nitrogen atmosphere at a temperature of 100 °C for 10 minutes. Label the resulting sample as PyDA.

[0032] Example 3: (1) Pre-evaporation treatment: clean the substrate by ultrasonic cleaning with deionized water and ethanol for 20 minutes, then remove the water and solvent on the surface of the substrate. Then, treat the substrate with ultraviolet ozone for 20 minutes.

[0033] (2) Sequential evaporation: evacuate the vacuum chamber to a vacuum degree of less than 10 -4 Evaporation can start at 10 Pa. The first step is to evaporate precursor A methylammonium iodide (MAI) at a rate of 0.04-0.05 nm / s to a thickness of 20-30 nm. The second step is to evaporate additive 5-aminopentanoic acid at a rate of 0.01-0.02 nm / s to a thickness of 5-10 nm. The third step is to evaporate PbI2 as precursor B at a rate of 0.04-0.06 nm / s to a thickness of 10-20 nm.

[0034] (3) Post-processing: anneal the film after evaporation in a nitrogen atmosphere at a temperature of 100 °C for 10 minutes.

[0035] Example 4: (1) Pre-evaporation treatment: clean the substrate by ultrasonic cleaning with deionized water and ethanol for 20 minutes, then remove the water and solvent on the surface of the substrate. Then, treat the substrate with ultraviolet ozone for 20 minutes.

[0036] (2) Sequential evaporation: evacuate the vacuum chamber to a vacuum degree of less than 10 -4 Evaporation can start at 10 Pa. The first step is to evaporate precursor A methylammonium iodide (MAI) at a rate of 0.04-0.05 nm / s to a thickness of 20-30 nm. The second step is to evaporate additive 5-aminopentanoic acid at a rate of 0.01-0.02 nm / s to a thickness of 5-10 nm. The third step is to evaporate PbI2 as precursor B at a rate of 0.04-0.06 nm / s to a thickness of 10-20 nm.

[0037] (3) Post-treatment: The film after evaporation is annealed in a nitrogen atmosphere at a temperature of 100 °C for 10 minutes.

[0038] Example 5: (1) Pretreatment of substrate before vapor deposition: Ultrasonic cleaning with deionized water and ethanol for 20 minutes, then removing moisture and solvent from the substrate surface; then UV ozone treatment of the treated substrate for 20 minutes.

[0039] (2) Reference Figure 3 Perform sequential vapor deposition: Evacuate the vacuum chamber until the vacuum level is less than 10. -4 Evaporation can begin at Pa. The first step involves evaporating precursor A, formamidinium hydroiodate, with the evaporation rate controlled at 0.04~0.05 nm / s and the film thickness at 20~30 nm. The second step involves evaporating the additive diphenylphosphamide, with the evaporation rate controlled at 0.01~0.02 nm / s and the film thickness at 5~10 nm. The third step involves evaporating PbI2 as precursor B, with the evaporation rate controlled at 0.04~0.06 nm / s and the film thickness at 10~20 nm.

[0040] (3) Post-treatment: The film after evaporation is annealed in a nitrogen atmosphere at a temperature of 100 °C for 10 minutes.

[0041] Example 6: (1) Pretreatment of substrate before vapor deposition: Ultrasonic cleaning with deionized water and ethanol for 20 minutes, then removing moisture and solvent from the substrate surface; then UV ozone treatment of the treated substrate for 20 minutes.

[0042] (2) Sequential vapor deposition: Evacuate the vacuum chamber until the vacuum level is less than 10. -4 Evaporation can begin at Pa. The first step involves simultaneously depositing precursor A, formamidinium hydroiodate, and additive 5-aminovaleric acid, controlling the deposition rate at 0.04–0.05 nm / s and the film thickness at 25–35 nm. The second step involves depositing PbI₂ as precursor B, controlling the deposition rate at 0.04–0.06 nm / s and the film thickness at 10–20 nm.

[0043] (3) Post-treatment: The film after evaporation is annealed in a nitrogen atmosphere at a temperature of 100°C for 10 minutes.

[0044] Comparative example: (1) Pretreatment of substrate before vapor deposition: ultrasonic cleaning with deionized water and ethanol for 20 minutes respectively, and then removing the moisture and solvent from the substrate surface; then treating the treated substrate with ultraviolet ozone for 20 minutes.

[0045] (2) Sequential vapor deposition: Evacuate the vacuum chamber until the vacuum level is less than 10. -4The evaporation can be started at Pa. In the first step, the precursor A methylamidine hydroiodide is evaporated, and the evaporation rate is controlled to be 0.04-0.05 nm / s, and the film thickness is 20-30 nm. In the second step, PbI2 as the precursor B is evaporated, and the evaporation rate is controlled to be 0.04-0.06 nm / s, and the film thickness is 10-20 nm.

[0046] (3) Post-processing: the thin film after evaporation is annealed in a nitrogen atmosphere, the annealing temperature is 100 ℃, and the annealing time is 10 minutes. The obtained sample is marked as no additive.

[0047] Example sample test: to confirm the influence of the method and additive of the present application on the carrier transport and lifetime in the perovskite thin film, the time-resolved photoluminescence spectrum test is performed on the samples of examples 1, 2 and the comparative example, and the results are shown in Figure 1 As can be seen from the figure, the method of the present application can effectively reduce the defects in the perovskite material and improve the crystalline quality of the perovskite thin film. The performance of the material of example 2 using pyridine-2,6-dicarboxamide is better than that of example 1 using 5-aminovaleric acid, which shows that the selection of the additive has a great influence on the improvement of the material performance.

[0048] To evaluate the influence of the method of the present application 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 is detected. The results are shown in Figure 2 As can be seen from the figure, compared with the comparative example without evaporating the additive, the material prepared by the method of the present application has a very high fluorescence quantum yield. The fluorescence quantum yield of the comparative example is less than 10%, while the fluorescence quantum yield of the material prepared by the method of the present application is close to 40%, and the yield of example 2 is even more than 80%, which is much higher than that of the comparative example, indicating that the method of the present application can significantly improve the luminescence potential of the material.

[0049] The electroluminescence quantum yield of the samples of examples 1, 2 and the comparative example is detected. The results are shown in Figure 3 Compared with the comparative example without evaporating the additive, the light-emitting diode with the perovskite light-emitting layer prepared by the method of the present application all shows a high electroluminescence external quantum efficiency. The electroluminescence external quantum efficiency of the comparative example is less than 4%, while the electroluminescence external quantum efficiency of the device based on the perovskite light-emitting layer prepared by the method of the present application is more than 10%, and the yield of example 2 is even more than 20%, which is much higher than that of the comparative example. As Figure 4 can be seen, the perovskite material prepared by the method of the present application shows good uniformity, and Figure 5 the large-size sample photo of the

[0050] For those skilled in the art, other various corresponding changes and modifications can be made to the above described technical solutions and concepts, and all these changes and modifications should belong to the protection scope of the claims of the present application.

Claims

1. A method for manufacturing a perovskite light-emitting device, comprising: The preparation of the perovskite layer of the light-emitting device comprises the following steps: vacuum vapor deposition of perovskite precursor A and an additive simultaneously or sequentially on a substrate on which a functional layer is deposited, then vacuum vapor deposition of perovskite precursor B, and annealing in one go. ​ The additive is a compound containing an amide, amino, carboxyl, phosphorus-oxygen double bond, sulfur-oxygen double bond, carbon-nitrogen double bond, pyrimidine or pyridine functional group. 2.The method of claim 1, wherein the perovskite light emitting device is prepared by the steps of: Comprise the following steps: Sequential vacuum vapor deposition of precursor A, an additive and precursor B on a substrate on which a functional layer is deposited, and annealing in one go.

3. The method for fabricating a perovskite light-emitting device according to claim 1 or 2, characterized in that, The additive is one of pyridine-2, 6-dicarboxamide, 5-aminovaleric acid, 2-picolinamide, phthalimide, fumaramide, suberamide, p-hydroxybenzenesulfonamide, diphenylphosphoramide and 3-[2-(2-aminoethoxy)ethoxy]-propionic acid.

4. The method for fabricating a perovskite light-emitting device according to claim 1 or 2, characterized in that, The precursor A or B of the perovskite is one or more of formamidinium hydrohalide, methylamine hydrohalide and cesium halide, or one or more of lead halide and tin halide.

5. The method for fabricating a perovskite light-emitting device according to claim 1 or 2, characterized in that, The rate of vacuum vapor deposition of the precursor A or precursor B is 0.04-1 nm / s, and the rate of vacuum vapor deposition of the additive is 0.01-1 nm / s.

6. The method for fabricating a perovskite light-emitting device according to claim 1 or 2, characterized in that, The thickness of the precursor A and the precursor B of the perovskite and the additive is 5-200 nm respectively.

7. The method for fabricating a perovskite light-emitting device according to claim 1 or 2, characterized in that, The thickness of the precursor A and the precursor B of the perovskite is 20-60 nm, and the thickness of the additive is 5-25 nm.

8. A perovskite light-emitting device prepared by the method of claim 1 or 2.

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