A method for preparing a perovskite polycrystalline light-emitting thin film with quantum dots as additive auxiliary growth

Abstract

The application discloses a method for preparing a perovskite polycrystalline luminescent film with quantum dots as an additive to assist growth, quantum dots are added into perovskite precursor liquid in a certain proportion to assist perovskite crystal growth in the spin coating process. The introduction of quantum dots can control the grain growth process of the perovskite polycrystalline film, promote the uniform growth of the grains and reduce the grain size, form a more dense and flat film structure, and is beneficial to improve the crystallization quality and photoelectric performance of the film. For example, by adjusting the addition amount of quantum dots and the reaction conditions, the growth rate and size distribution of perovskite grains can be controlled, the microstructure of the film is improved, meanwhile, the quantum dots can interact with the defect sites in the perovskite polycrystalline film, effectively passivate the surface defects, reduce the non-radiative recombination center, thereby improving the luminescent efficiency and stability of the film. The introduction of quantum dots can also improve the interface contact between the perovskite polycrystalline film and other functional layers, and reduce the interface energy barrier.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of perovskite light-emitting diodes, and particularly relates to a method for preparing a perovskite polycrystalline light-emitting film with quantum dots as an additive for assisting growth. BACKGROUND

[0002] Perovskite light-emitting diodes (PeLEDs) have attracted extensive attention in the field of optoelectronics in recent years as a new emerging light-emitting technology. Perovskite materials are considered as potential materials to replace traditional organic light-emitting diodes (OLEDs) due to their excellent optoelectronic properties, such as high light absorption coefficient, tunable band gap and high carrier mobility. PeLEDs have high light conversion efficiency and low production cost, and can realize high brightness and wide color gamut at room temperature, thus showing wide application prospects in display technology, lighting and other optoelectronic applications.

[0003] The quality of perovskite thin films is crucial in perovskite light-emitting diodes (PeLEDs), as it directly affects the optoelectronic performance, stability and efficiency of the devices. Perovskite materials have wide application prospects in the field of light-emitting diodes due to their excellent optoelectronic properties, such as high light absorption coefficient, good carrier mobility and tunable band gap. However, to achieve high-efficiency perovskite light-emitting diodes, high-quality perovskite thin films are required.

[0004] High-quality perovskite thin films usually have uniform thickness, low defect density and good crystal structure. 1. The grain size of perovskite thin films is closely related to the optoelectronic properties, and reducing the grain size helps to reduce carrier recombination, improve current efficiency and light output. 2. Defects such as grain boundaries, hole or electron traps often lead to carrier recombination and energy loss, thus reducing the brightness and efficiency of the device. 3. The surface quality of the thin film is also a key factor affecting the performance of PeLEDs, and surface defects or unevenness can cause rapid recombination of electrons and holes, thus reducing the light-emitting efficiency. Therefore, optimizing the preparation process of the thin film, such as solution processing, annealing, adding additives, etc., can effectively improve the quality of the thin film and enhance the overall performance of the perovskite light-emitting diode.

[0005] In summary, the optimization of perovskite thin film quality is crucial for improving the efficiency, stability and service life of perovskite light-emitting diodes. SUMMARY

[0006] Based on the importance of perovskite thin film quality for perovskite light-emitting devices, it is necessary to find a method that can assist the growth of perovskite crystals in various aspects, reduce defects and optimize the quality of the thin film. The present application provides a method for preparing a perovskite polycrystalline light-emitting film with quantum dots as an additive for assisting growth.

[0007] In order to achieve the above object, the present application adopts the following technical solutions to achieve the above object:

[0008] The application discloses a method for preparing a perovskite polycrystalline luminescent film with quantum dots as an additive for auxiliary growth, and comprises the following steps:

[0009] S1: preparing a perovskite precursor solution A

[0010] In a nitrogen glove box, cesium iodide, lead iodide, phenethylamine iodide and 1-naphthylmethylammonium iodide are dissolved in a polar organic solvent at a molar ratio of X:X:X:Y, and then stirring is carried out at 40 DEG C in the nitrogen glove box for at least 2 hours to obtain the perovskite precursor solution A;

[0011] S2: preparing a perovskite quantum dot additive solution

[0012] A certain amount of 1-octadecene is loaded in a three-necked round-bottom flask, and lead iodide, lead bromide, benzyl bromide amine and benzyl iodide amine are mixed in the three-necked round-bottom flask at a molar ratio of x:y:y:z in a nitrogen glove box, and then the mixture is quickly transferred into the three-necked round-bottom flask and mixed with the 1-octadecene, and then the three-necked round-bottom flask is vacuumized, and then the oil bath of the three-necked round-bottom flask is heated for 20 minutes. Then, a certain amount of oleic acid is injected into the three-necked round-bottom flask at a certain temperature A1 under a nitrogen flow, and after injection, the three-necked round-bottom flask is vacuumized, and then the oil bath of the three-necked round-bottom flask is heated for 20 minutes; then, a certain amount of preheated cesium oleate is quickly injected into the three-necked round-bottom flask, and then the three-necked round-bottom flask is immersed in a cold water bath and cooled to room temperature. After that, the mixture solution in the three-necked round-bottom flask is centrifuged, and after centrifugation, the upper solution is collected to obtain the perovskite quantum dot additive solution.

[0013] S3: preparing a perovskite precursor solution B

[0014] A certain amount of the perovskite quantum dot additive solution is added to the perovskite precursor solution A, and after sufficient stirring, the perovskite precursor solution B is obtained.

[0015] S4: the perovskite precursor solution B is spin-coated on a glass substrate in a nitrogen glove box at a certain rotating speed and time, and then annealing treatment is carried out to obtain a perovskite film doped with quantum dots.

[0016] Further, the polar organic solvent in S1 is one of DMSO or DMF.

[0017] Further, in S1, 0.7≤X≤1 and 1.4≤Y≤2.

[0018] Further, in S1, the cesium iodide, the lead iodide and the phenethylamine iodide are all 0.05 m, and the 1-naphthylmethylammonium iodide is 0.1 m.

[0019] Further, in S2, 0.8≤x≤1.2, 0.4≤y≤0.6, 0.7≤z≤0.9.

[0020] Further, in S2, the lead iodide is 0.5 m, the lead bromide and benzyl bromide amine are both 0.25 m, and the benzyl iodide amine is 0.42 m.

[0021] Further, in S2, the temperature A1 is 100-120℃.

[0022] Further, in S4, the spin coating rotation speed is 2000-4000 rpm, the spin coating time is 40-100 s, the annealing temperature is 60-100℃, and the annealing time is 5-8 min.

[0023] Further, the concentration of the quantum dot additive solution in the perovskite precursor solution B is 2-10 vol%.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] The present application discloses a method for preparing perovskite polycrystalline luminescent films with quantum dots as additives to assist growth, which has multiple advantages in optimizing the quality of perovskite films and is expected to become a widely used technology.

[0026] 1. The introduction of quantum dots as additives can effectively regulate the crystal growth process of perovskite films. The size and surface characteristics of quantum dots can interact with the nucleation and growth process of perovskite crystals, thereby promoting uniform nucleation and crystal growth of perovskite films. This helps to reduce defects, optimize the crystal quality of the film, form smaller grains, and thus improve the photoelectric performance.

[0027] 2. Quantum dots themselves have excellent electron and hole transport performance, and can act as carrier transport channels in perovskite films. Quantum dots can help improve the mobility of carriers in perovskite materials, reduce carrier recombination, and thus improve the light-emitting efficiency.

[0028] 3. Quantum dots can form stable interface structures on the interface of perovskite films, improving the charge injection and transport process. Through the surface modification of quantum dot additives, interface defects can be effectively reduced, thereby reducing non-radiative recombination and improving photoelectric conversion efficiency.

[0029] 4. Quantum dots have excellent optical properties, including strong absorption and fluorescence emission characteristics. When quantum dots are mixed with perovskite materials, they can adjust the light absorption and luminescence properties of the film, especially in improving the spectral width and luminous intensity.

[0030] 5. The method in which quantum dots are added as additives to the perovskite precursor solution can regulate the growth of perovskite crystals, reduce carrier recombination, improve carrier transport performance, reduce interface defects, and stabilize the interface structure of the perovskite film. In summary, quantum dots as additives can play a multi-faceted optimization role in the growth process of perovskite polycrystalline films, thereby enhancing the efficiency and stability of perovskite light-emitting diodes.

[0031] 6. The luminescent color of the perovskite luminescent film can be adjusted according to the halogen element in the perovskite precursor solution. Based on the different ratios of I - , Br - , Cl - halide ions, red (620-650 nm), green (510-570 nm), blue (450-490) and other different wavebands of light can be achieved. The present application takes the preparation of a red perovskite luminescent film as an example to describe a method of growing a red perovskite polycrystalline luminescent film with red quantum dots as additives. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a perovskite film prepared by the present application in a N2 environment;

[0033] Figure 2 is a spectrum of perovskite films doped with quantum dot additives of different proportions prepared by the present application;

[0034] Figure 3 is a SEM image of perovskite films doped with quantum dot additives of different proportions prepared by the present application. DETAILED DESCRIPTION

[0035] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the present application after reading the content taught by the present application, and these equivalent forms also fall within the scope of the appended claims.

[0036] Example 1

[0037] A method for preparing a perovskite polycrystalline luminescent film with quantum dots as additives includes the following steps:

[0038] S1: preparing a perovskite precursor solution A

[0039] In a nitrogen glove box, cesium iodide, lead iodide, phenethylamine iodide and 1-naphthylmethyl ammonium iodide are dissolved in DMSO solution at a molar ratio of 0.05m:0.05m:0.05m:0.1m, then stirred at 40°C in a nitrogen glove box for 2h to obtain the perovskite precursor solution A;

[0040] S2: Preparation of perovskite quantum dot additive solution

[0041] A three-necked round-bottom flask was charged with 20 mL of 1-octadecene, and in a nitrogen glove box, lead iodide, lead bromide, benzyl bromide amine and benzyl iodide amine were mixed in a molar ratio of 0.5m:0.25m:0.25m:0.42m, and then the mixture was quickly transferred into the above-mentioned three-necked round-bottom flask and mixed with 1-octadecene, and then the three-necked round-bottom flask was vacuumed, and then the three-necked round-bottom flask was heated in an oil bath at 100°C for 20 min. Then, 2 mL of oleic acid was injected into the three-necked round-bottom flask at 120°C under a nitrogen stream, and after injection, the three-necked round-bottom flask was vacuumed, and then the three-necked round-bottom flask was heated in an oil bath at 120°C for 20 min; then, 1 mL of preheated cesium oleate was quickly injected into the three-necked round-bottom flask, and then the three-necked round-bottom flask was immersed in a cold water bath and cooled to room temperature. After that, the mixed solution in the three-necked round-bottom flask was centrifuged at 12000 rpm for 10 min, and after centrifugation, the upper solution was collected to obtain a perovskite quantum dot additive solution.

[0042] S3: Preparation of perovskite precursor solution B

[0043] 9uL of perovskite quantum dot additive solution was added to 291uL of perovskite precursor solution A, and after stirring for 10 min, perovskite precursor solution B was obtained.

[0044] S4: The perovskite precursor solution B1 was spin-coated on a glass substrate in a nitrogen glove box at 4000 rpm for 90 s, and then annealed at 80°C for 6 min to obtain a quantum dot-doped perovskite thin film (quantum dot additive content of 3 vol%).

[0045] Example 2

[0046] S1: Preparation of perovskite precursor solution A

[0047] In a nitrogen glove box, cesium iodide, lead iodide, phenethylamine iodide and 1-naphthylmethylammonium iodide were dissolved in DMSO solution in a molar ratio of 0.05m:0.05m:0.05m:0.1m, and then stirred at 40°C for 3h in a nitrogen glove box to obtain perovskite precursor solution A;

[0048] S2: Preparation of perovskite quantum dot additive solution

[0049] A three-necked round-bottom flask was charged with 20 mL of 1-octadecene, and in a nitrogen glove box, lead iodide, lead bromide, benzyl amine bromide and benzyl amine iodide were mixed in a molar ratio of 0.5 m: 0.25 m: 0.25 m: 0.42 m, and then the mixture was quickly transferred into the above-mentioned three-necked round-bottom flask and mixed with 1-octadecene, and then the three-necked round-bottom flask was vacuumed, and then the three-necked round-bottom flask was heated in an oil bath at 100 °C for 20 min. Then, 2 mL of oleic acid was injected into the three-necked round-bottom flask at 120 °C under a nitrogen stream, and after injection, the three-necked round-bottom flask was continuously vacuumed, and then the three-necked round-bottom flask was heated in an oil bath at 120 °C for 20 min; then, 1 mL of preheated cesium oleate was quickly injected into the three-necked round-bottom flask, and then the three-necked round-bottom flask was immersed in a cold water bath and cooled to room temperature. After that, the mixed solution in the three-necked round-bottom flask was centrifuged at 12000 rpm for 10 min, and after centrifugation, the upper solution was collected to obtain a perovskite quantum dot additive solution.

[0050] S3: Preparation of perovskite precursor solution B

[0051] 15 uL of the perovskite quantum dot additive solution was added to 285 uL of the perovskite precursor solution A, and after stirring for 10 min, a perovskite precursor solution B was obtained.

[0052] S4: The perovskite precursor solution B was spin-coated on a glass substrate in a nitrogen glove box at 4000 rpm for 90 s, and then annealed at 80 °C for 6 min to obtain a quantum dot-doped perovskite thin film (quantum dot additive content of 5 vol%).

[0053] Example 3

[0054] S1: Preparation of perovskite precursor solution A

[0055] In a nitrogen glove box, cesium iodide, lead iodide, phenethylamine iodide and 1- naphthylmethylammonium iodide were dissolved in DMSO solution in a molar ratio of 0.05 m: 0.05 m: 0.05 m: 0.1 m, and then stirred at 40 °C for 4 h in the same nitrogen glove box to obtain a perovskite precursor solution A;

[0056] S2: Preparation of perovskite quantum dot additive solution

[0057] A three-necked round-bottom flask was charged with 20 mL of 1-octadecene, and in a nitrogen glove box, lead iodide, lead bromide, benzyl amine bromide and benzyl amine iodide were mixed in a molar ratio of 0.5 m: 0.25 m: 0.25 m: 0.42 m, and then the mixture was quickly transferred into the above-mentioned three-necked round-bottom flask and mixed with 1-octadecene, and then the three-necked round-bottom flask was vacuumed, and then the three-necked round-bottom flask was heated in an oil bath at 100 °C for 20 min. Then, 2 mL of oleic acid was injected into the three-necked round-bottom flask at 120 °C under a nitrogen stream, and after injection, the three-necked round-bottom flask was continuously vacuumed, and then the three-necked round-bottom flask was heated in an oil bath at 120 °C for 20 min; then, 1 mL of preheated cesium oleate was quickly injected into the three-necked round-bottom flask, and then the three-necked round-bottom flask was immersed in a cold water bath and cooled to room temperature. After that, the mixed solution in the three-necked round-bottom flask was centrifuged at 12000 rpm for 10 min, and after centrifugation, the upper solution was collected to obtain a perovskite quantum dot additive solution.

[0058] S3: Preparation of perovskite precursor solution B

[0059] 21 uL of the perovskite quantum dot additive solution was added to 279 uL of the perovskite precursor solution A, and after stirring for 10 min, a perovskite precursor solution B was obtained.

[0060] S4: The perovskite precursor solution B3 was spin-coated on a glass substrate in a nitrogen glove box at 4000 rpm for 90 s, and then annealed at 80 °C for 6 min to obtain a quantum dot-doped perovskite thin film (quantum dot additive content of 7 vol%).

[0061] Comparative Example

[0062] S1: Preparation of perovskite precursor solution A

[0063] In a nitrogen glove box, cesium iodide, lead iodide, phenethylamine iodide and 1-naphthylmethylammonium iodide were dissolved in DMSO solution in a molar ratio of 0.05 m: 0.05 m: 0.05 m: 0.1 m, and then stirred at 40 °C for 2 h in the same nitrogen glove box to obtain a perovskite precursor solution A;

[0064] S2: The perovskite precursor solution A was spin-coated on a glass substrate in a nitrogen glove box at 4000 rpm for 90 s, and then annealed at 80 °C for 6 min to obtain a perovskite thin film without quantum dot doping (quantum dot additive content of 0 vol%).

[0065] Comparing the film quality, SEM images and PL spectra of the perovskite films doped with different amounts of quantum dot additives prepared in the above comparative examples and examples, it is found that appropriate amount of quantum dot additive doping has obvious optimization effect on the film quality, stability and luminescence intensity of the perovskite film; compared with the traditional film optimization method, the quantum dot additive assisted film forming method of the present application is simple in operation and remarkable in effect, meanwhile, the quantum dots are usually low-cost and easy-to-synthesize materials, which are compatible with the preparation process of the perovskite film, the introduction of the quantum dots will not greatly increase the cost, and the quantum dots can be combined with the perovskite material through simple processing methods such as solution method and thermal injection, which is convenient for large-scale production and suitable for application in modern production lines.

[0066] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application, any modification made according to the technical idea of the present application on the basis of the technical scheme shall fall within the protection scope of the claims of the present application.

Claims

1. A method for preparing perovskite polycrystalline light-emitting thin films with quantum dots as additives to assist in the growth of perovskite polycrystalline films, characterized in that, Includes the following steps: S1: Prepare perovskite precursor solution A; S2: Prepare a perovskite quantum dot additive solution; S3: Prepare perovskite precursor solution B; S4: The perovskite precursor solution B is coated onto a glass substrate by rotation at a certain speed and time in a nitrogen glove box, followed by annealing to obtain a perovskite film doped with quantum dots. Step S1 is as follows: Cesium iodide, lead iodide, phenethylamine iodide and 1-naphthylmethylammonium iodide were dissolved in a polar organic solvent in a nitrogen glove box at a molar ratio of X:X:X:Y. Then, the mixture was stirred at 40°C for at least 2 hours in the same nitrogen glove box to obtain perovskite precursor solution A. Step S2 is as follows: A certain amount of 1-octadecene was placed in a three-necked round-bottom flask. Lead iodide, lead bromide, benzylamine bromide, and benzylamine iodide were mixed in a nitrogen glove box at a molar ratio of x:y:y:z. The mixture was then quickly transferred to the three-necked round-bottom flask and mixed with the 1-octadecene. The three-necked round-bottom flask was then evacuated and heated in an oil bath for 20 minutes. Next, a certain amount of oleic acid was injected into the three-necked round-bottom flask at a certain temperature A1 under a nitrogen flow. After injection, the three-necked round-bottom flask was evacuated again and heated in an oil bath for 20 minutes. Then, a certain amount of preheated cesium oleate was quickly injected into the three-necked round-bottom flask. The three-necked round-bottom flask was then immersed in a cold water bath and cooled to room temperature. The mixture solution in the three-necked round-bottom flask was then centrifuged, and the supernatant solution was collected to obtain a perovskite quantum dot additive solution. Step S3 is as follows: A certain amount of perovskite quantum dot additive solution was added to perovskite precursor solution A, and after thorough stirring, perovskite precursor solution B was obtained.

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