Method for preparing perovskite polycrystalline light-emitting film with quantum dots as additive for auxiliary growth

Abstract

The invention discloses a method for preparing a perovskite polycrystalline light-emitting film with quantum dots as an additive for assisting growth, which comprises the following steps: adding the quantum dots as the additive into a perovskite precursor solution according to a certain proportion, and assisting the growth of perovskite crystals in a spin coating process. The introduction of the quantum dots can regulate and control the grain growth process of the perovskite polycrystalline film, promote the uniform growth of grains and reduce the grain size, form a more compact and smoother film structure, and facilitate the improvement of the crystal quality and photoelectric properties of the film. For example, by adjusting the adding amount and reaction conditions of the quantum dots, the growth rate and size distribution of perovskite grains can be controlled, the microstructure of the thin film can be improved, meanwhile, the quantum dots can interact with defect sites in the perovskite polycrystalline thin film, surface defects are effectively passivated, non-radiative recombination centers are reduced, and the performance of the thin film is improved. Therefore, the luminous efficiency and stability of the film are improved. The introduction of the 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 invention belongs to the technical field of perovskite light-emitting diodes, and in particular relates to a method for preparing a perovskite polycrystalline light-emitting film using quantum dots as additives to assist in the growth of the film. Background Art

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

[0003] The importance of perovskite film quality in perovskite light-emitting diodes (PeLEDs) is self-evident, as it directly affects the optoelectronic performance, stability, and efficiency of the device. Perovskite materials have broad 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 adjustable band gap. However, to achieve efficient perovskite light-emitting diodes, it is first necessary to obtain high-quality perovskite films.

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

[0005] In summary, optimization of perovskite film quality is the key to improving the efficiency, stability and service life of perovskite light-emitting diodes. Summary of the invention

[0006] Based on the importance of perovskite film quality to perovskite light-emitting devices, it is necessary to find a method that can assist perovskite crystal growth in various aspects, reduce defects, and optimize film quality. The present invention provides a method for preparing a perovskite polycrystalline light-emitting film using quantum dots as additives to assist in the growth of the perovskite light-emitting device.

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

[0008] The present invention discloses a method for preparing a perovskite polycrystalline luminescent film using quantum dots as additives to assist in the growth of the film, comprising the following steps:

[0009] S1: Preparation of perovskite precursor solution A

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

[0011] S2: Preparation of perovskite quantum dot additive solution

[0012] A certain amount of 1-octadecene is placed in a three-necked round-bottom flask, and lead iodide, lead bromide, benzyl ammonium bromide and benzyl ammonium iodide are mixed in a molar ratio of x:y:y:z in a nitrogen glove box, and then the mixture is quickly transferred to the above three-necked round-bottom flask and mixed with 1-octadecene, and then the three-necked round-bottom flask is evacuated, and then the three-necked round-bottom flask is heated in an oil bath 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 the three-necked round-bottom flask is continuously evacuated after injection, and then the three-necked round-bottom flask is heated in an oil bath 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 the upper layer solution is collected after centrifugation to obtain a perovskite quantum dot additive solution.

[0013] S3: Preparation of perovskite precursor solution B

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

[0015] S4: Spin-coat the perovskite precursor solution B on a glass substrate at a certain rotation speed and time in a nitrogen glove box, and then anneal to obtain a quantum dot-doped perovskite film.

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

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

[0018] Furthermore, in S1, the contents of cesium iodide, lead iodide and phenylethylamine iodide are all 0.05 m, and the content of 1-naphthylmethylammonium iodide is 0.1 m.

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

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

[0021] Furthermore, the temperature A1 in S2 is 100°C to 120°C.

[0022] Furthermore, in S4, the spin coating speed is 2000-4000 rpm, the spin coating time is 40s-100s; the annealing temperature is 60-100°C, and the annealing time is 5min-8min.

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

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

[0025] The invention discloses a method for preparing a polycrystalline perovskite light-emitting film using quantum dots as additives to assist in the growth of the film. The method of using quantum dots as additives to optimize the quality of the perovskite film has multiple significant advantages 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 optoelectronic performance.

[0027] 2. Quantum dots have excellent electron and hole transport properties 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 luminescence efficiency.

[0028] 3. Quantum dots can form a stable interface structure on the interface of perovskite film, improving the charge injection and transfer process. Through the surface modification of quantum dot additives, the interface defects can be effectively reduced, thereby reducing non-radiative recombination and improving the 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 characteristics of the film, especially in improving the spectral width and luminescence intensity.

[0030] 5. In this method, quantum dots are added as additives to the perovskite precursor solution to regulate the growth of perovskite crystals, reduce carrier recombination, improve carrier transport performance, reduce interface defects, and stabilize the interface structure of perovskite films. In short, 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 elements in the perovskite precursor solution. - Br - , Cl - The ratio of halogen ions can achieve light emission in different wavelengths, such as red (620-650nm), green (510-570nm), and blue (450-490). The present invention takes the preparation of red light perovskite light-emitting film as an example to describe the method of using red light quantum dots as additives to assist the growth of red light perovskite polycrystalline light-emitting film. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a comparison diagram of the perovskite film of the present invention in a N2 environment;

[0033] Figure 2 The spectra of perovskite films doped with quantum dot additives in different proportions prepared by the present invention;

[0034] Figure 3 These are SEM images of perovskite films doped with quantum dot additives in different proportions prepared by the present invention. DETAILED DESCRIPTION

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

[0036] Example 1

[0037] A method for preparing a perovskite polycrystalline light-emitting film using quantum dots as additives to assist in the growth of the film comprises the following steps:

[0038] S1: Preparation of perovskite precursor solution A

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

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

[0041] 20 mL of 1-octadecene was placed in a three-necked round-bottom flask, and lead iodide, lead bromide, benzyl ammonium bromide and benzyl ammonium iodide were mixed in a nitrogen glove box at a molar ratio of 0.5 m: 0.25 m: 0.25 m: 0.42 m, and then the mixture was quickly transferred to the above three-necked round-bottom flask and mixed with 1-octadecene, and then the three-necked round-bottom flask was evacuated, and then the three-necked round-bottom flask was heated in an oil bath at 100°C for 20 minutes. Then, 2 mL of oleic acid was injected into the three-necked round-bottom flask at 120°C under a nitrogen flow, and after the injection, the three-necked round-bottom flask was continuously evacuated, and then the three-necked round-bottom flask was heated in an oil bath at 120°C for 20 minutes; 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. Then, the mixture solution in the three-necked round-bottom flask was centrifuged at 12000 rpm for 10 min, and the upper layer solution was collected after centrifugation to obtain a perovskite quantum dot additive solution.

[0042] S3: Preparation of perovskite precursor solution B

[0043] 9uL of the perovskite quantum dot additive solution was added to 291uL of the perovskite precursor solution A and stirred for 10 minutes to obtain the perovskite precursor solution B.

[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 film (the quantum dot additive content was 3 vol%).

[0045] Example 2

[0046] S1: Preparation of perovskite precursor solution A

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

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

[0049] 20 mL of 1-octadecene was placed in a three-necked round-bottom flask, and lead iodide, lead bromide, benzyl ammonium bromide and benzyl ammonium iodide were mixed in a nitrogen glove box at a molar ratio of 0.5 m: 0.25 m: 0.25 m: 0.42 m, and then the mixture was quickly transferred to the above three-necked round-bottom flask and mixed with 1-octadecene, and then the three-necked round-bottom flask was evacuated, and then the three-necked round-bottom flask was heated in an oil bath at 100°C for 20 minutes. Then, 2 mL of oleic acid was injected into the three-necked round-bottom flask at 120°C under a nitrogen flow, and after the injection, the three-necked round-bottom flask was continuously evacuated, and then the three-necked round-bottom flask was heated in an oil bath at 120°C for 20 minutes; 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. Then, the mixture solution in the three-necked round-bottom flask was centrifuged at 12000 rpm for 10 min, and the upper layer solution was collected after centrifugation 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 the perovskite precursor solution B was obtained after stirring for 10 min.

[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 film (the quantum dot additive content was 5 vol%).

[0053] Example 3

[0054] S1: Preparation of perovskite precursor solution A

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

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

[0057] 20 mL of 1-octadecene was placed in a three-necked round-bottom flask, and lead iodide, lead bromide, benzyl ammonium bromide and benzyl ammonium iodide were mixed in a nitrogen glove box at a molar ratio of 0.5 m: 0.25 m: 0.25 m: 0.42 m, and then the mixture was quickly transferred to the above three-necked round-bottom flask and mixed with 1-octadecene, and then the three-necked round-bottom flask was evacuated, and then the three-necked round-bottom flask was heated in an oil bath at 100°C for 20 minutes. Then, 2 mL of oleic acid was injected into the three-necked round-bottom flask at 120°C under a nitrogen flow, and after the injection, the three-necked round-bottom flask was continuously evacuated, and then the three-necked round-bottom flask was heated in an oil bath at 120°C for 20 minutes; 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. Then, the mixture solution in the three-necked round-bottom flask was centrifuged at 12000 rpm for 10 min, and the upper layer solution was collected after centrifugation to obtain a perovskite quantum dot additive solution.

[0058] S3: Preparation of perovskite precursor solution B

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

[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 film (the quantum dot additive content was 7 vol%).

[0061] Comparative Example

[0062] S1: Preparation of perovskite precursor solution A

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

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

[0065] The film quality, SEM images and PL spectra of the perovskite films doped with different quantum dot additives prepared in the above comparative examples and embodiments are compared. The appropriate amount of quantum dot additive doping has a significant 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 formation method of the present invention is simple to operate and has significant effects. At the same time, quantum dots are generally low-cost, easy-to-synthesize materials, which are compatible with the preparation process of perovskite films. The introduction of quantum dots will not significantly increase the cost, and quantum dots can be combined with perovskite materials through simple processing methods such as solution method and hot injection, which is convenient for large-scale production and suitable for application in modern production lines.

[0066] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a perovskite polycrystalline light-emitting film using quantum dots as additives to assist in the growth of the film, characterized in that: The following steps are involved: S1: preparing perovskite precursor solution A; S2: preparing perovskite quantum dot additive solution; S3: preparing perovskite precursor solution B; S4: Spin-coat the perovskite precursor solution B on a glass substrate at a certain rotation speed and time in a nitrogen glove box, and then anneal to obtain a quantum dot-doped perovskite film.

2. A method for preparing a perovskite polycrystalline light-emitting thin film using quantum dots as additives as claimed in claim 1, characterized in that: Step S1 is specifically as follows: Cesium iodide, lead iodide, phenylethylamine iodide and 1-naphthylmethylammonium iodide were dissolved in a polar organic solvent at a molar ratio of X:X:X:Y in a nitrogen glove box, and then stirred at 40° C. for at least 2 hours in the nitrogen glove box to obtain a perovskite precursor solution A.

3. A method for preparing a perovskite polycrystalline light-emitting film using quantum dots as additives as claimed in claim 1, characterized in that: Step S2 is specifically as follows: A certain amount of 1-octadecene is placed in a three-necked round-bottom flask, and lead iodide, lead bromide, benzyl ammonium bromide and benzyl ammonium iodide are mixed in a molar ratio of x:y:y:z in a nitrogen glove box, and then the mixture is quickly transferred to the above three-necked round-bottom flask and mixed with 1-octadecene, and then the three-necked round-bottom flask is evacuated, and then the three-necked round-bottom flask is heated in an oil bath 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 the injection, the three-necked round-bottom flask is continuously evacuated, and then the three-necked round-bottom flask is heated in an oil bath 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; then the mixture solution in the three-necked round-bottom flask is centrifuged, and the upper layer solution is collected after centrifugation to obtain a perovskite quantum dot additive solution.

4. A method for preparing a perovskite polycrystalline light-emitting thin film using quantum dots as additives as claimed in claim 1, characterized in that: Step S3 is specifically as follows: A certain amount of perovskite quantum dot additive solution is added to the perovskite precursor solution A, and the perovskite precursor solution B is obtained after sufficient stirring.

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