阅读说明：本技术 一种CsPbI3混相钙钛矿薄膜及其可控制备方法 (CsPbI3Mixed phase perovskite film and controllable preparation method thereof ) 是由 陈嘉伟 曾海波 李晓明 宋继中 魏昌庭 于 2020-06-29 设计创作，主要内容包括：本发明涉及一种CsPbI<Sub>3</Sub>混相钙钛矿薄膜及其可控制备方法,包括以下操作步骤：步骤1：将十八烯、油胺、油酸和碘化铅加入三口烧瓶中,在真空条件下140℃~180℃加热并搅拌,作为反应溶剂；步骤2：将硬脂酸铯、油酸溶解在十八烯中,形成前驱体溶液；步骤3：将前驱体溶液快速注入到反应溶剂中,迅速水冷,然后经离心提纯即制得钙钛矿CsPbI<Sub>3</Sub>量子点；步骤4：取CsPbI<Sub>3</Sub>量子点的分散液在洁净的玻璃片表面进行旋涂,并在大气环境下进行热处理,得到CsPbI<Sub>3</Sub>混相钙钛矿薄膜。由本方法制得的CsPbI<Sub>3</Sub>混相钙钛矿薄膜。本发明使用CsPbI<Sub>3</Sub>获得单体发射白光,材料新颖；基于全无机钙钛矿材料,相比传统钙钛矿材料更稳定；通过热处理的温度和时间实现CsPbI<Sub>3</Sub>的相调控,方法简单易施行。(The invention relates to CsPbI 3 The mixed phase perovskite thin film and the controllable preparation method thereof comprise the following operation steps: step 1: adding octadecene, oleylamine, oleic acid and lead iodide into a three-neck flask, heating and stirring at 140-180 ℃ under a vacuum condition to serve as a reaction solvent; step 2: dissolving cesium stearate and oleic acid in octadecene to form a precursor solution; and step 3: quickly injecting the precursor solution into a reaction solvent, quickly cooling by water, and then centrifugally purifying to obtain the perovskite CsPbI 3 Quantum dots; and 4, step 4: taking CsPbI 3 Spin coating the dispersion liquid of the quantum dots on the surface of a clean glass sheet, and performing heat treatment in the atmospheric environment to obtain CsPbI 3 A mixed phase perovskite thin film. CsPbI prepared by the method 3 A mixed phase perovskite thin film. The invention usesCsPbI 3 The monomer emission white light is obtained, and the material is novel; based on the all-inorganic perovskite material, the material is more stable than the traditional perovskite material; CsPbI achievement by temperature and time of thermal treatment 3 The method is simple and easy to implement.)

1. Controllable preparation CsPbI₃The method for preparing the mixed phase perovskite thin film is characterized by comprising the following steps: the method comprises the following operation steps:

step 1: adding octadecene, oleylamine, oleic acid and lead iodide into a three-neck flask, heating and stirring at 140-180 ℃ under a vacuum condition to serve as a reaction solvent;

step 2: dissolving cesium stearate and oleic acid in octadecene to form a precursor solution;

and step 3: quickly injecting the precursor solution into a reaction solvent, quickly cooling by water, growing the quantum dot nuclei, and then centrifugally purifying to remove redundant long-chain organic ligands on the surfaces of the quantum dots so as to promote the transport of current carriers, namely the perovskite CsPbI is prepared₃Quantum dots;

and 4, step 4: perovskite CsPbI₃Quantum dots are dispersed in a solvent to obtain CsPbI₃Dispersing liquid of quantum dots, CsPbI₃Spin coating the quantum dot dispersion on the surface of a clean glass sheet, and heat treating in atmospheric environment, CsPbI₃The black phase can change phase under the action of water and oxygen, part of the black phase can be converted into yellow phase, and CsPbI is obtained by controlling the temperature and the time₃The mixed phase perovskite thin film has large contact surface area of the black phase and the yellow phase, so that the mixed phase thin film well combines the excellent photoelectric property and carrier transport property of the black phase and the wide spectrum of the yellow phase, meanwhile, the black phase effectively supplements the red spectrum part, and the two phases are cooperatively matched to realize the spectrum coverage of the whole visible light and obtain the emission of the white light of the monomer.

2. Controllable preparation CsPbI according to claim 1₃The method for preparing the mixed phase perovskite thin film is characterized by comprising the following steps: in the reaction solvent prepared in the step 1, the volume ratio of oleic acid to octadecene is 1: 10-20, and the oleic acid and lead iodide have molThe molar ratio is 1: 1-2, and the volume ratio of the oleic acid to the oleylamine is 1: 1-2.

3. Controllable preparation CsPbI according to claim 1₃The method for preparing the mixed phase perovskite thin film is characterized by comprising the following steps: the volume ratio of oleic acid to octadecene in the precursor solution prepared in the step 2 is 1: 10-20, and the molar ratio of oleic acid to cesium stearate is 1: 1-2.

4. Controllable preparation CsPbI according to claim 1₃The method for preparing the mixed phase perovskite thin film is characterized by comprising the following steps: the stirring speed in the step 1 is 600-800 r/min.

5. Controllable preparation CsPbI according to claim 1₃The method for preparing the mixed phase perovskite thin film is characterized by comprising the following steps: the volume ratio of the precursor solution to the reaction solvent in the step 3 is 1: 10-20.

6. Controllable preparation CsPbI according to claim 1₃The method for preparing the mixed phase perovskite thin film is characterized by comprising the following steps: the centrifugal purification process in the step 3 comprises the following steps: dissolving the water-cooled precursor solution and the reaction solvent mixed solution into a flocculating agent, stirring and mixing uniformly, then placing the flocculating agent on a centrifuge for centrifugation, attaching the precipitate to the side wall after centrifugation, and pouring out the solution to obtain the precipitate, namely the perovskite CsPbI₃The flocculant is methanol, isopropanol, acetone, n-butanol or tert-butanol.

7. Controllable preparation CsPbI according to claim 1₃The method for preparing the mixed phase perovskite thin film is characterized by comprising the following steps: the solvent in the step 4 is selected from n-octane, n-hexane or toluene, CsPbI₃The concentration of the dispersion of quantum dots was 15 mg/mL.

8. Controllable preparation CsPbI according to claim 1₃The method for preparing the mixed phase perovskite thin film is characterized by comprising the following steps: CsPbI in the step 4₃In the preparation of the dispersion of quantum dotsAdding a solvent into the precipitate obtained in the step 3 and stirring until the precipitate is completely dissolved.

9. Controllable preparation CsPbI according to claim 1₃The method for preparing the mixed phase perovskite thin film is characterized by comprising the following steps: the relative humidity of the environment for heat treatment in the step 4 is 40-60%, the time for heat treatment is 20-60min, and the treatment temperature is 120-140 ℃.

10.CsPbI₃The mixed phase perovskite thin film is characterized in that: made by the process of any preceding claim.

Technical Field

The invention relates to CsPbI₃A mixed phase perovskite film and a controllable preparation method thereof, belonging to the technical field of novel nano materials.

Background

White electroluminescent light is a phenomenon simulating natural light, and has become a common and important daily lighting means in people's daily life, such as backlight in liquid crystal displays or indoor/street lighting. Generally, commercial electroluminescent white light is mainly realized by covering a yellow phosphor on a blue chip, but the color rendering index is low and the luminous efficiency is low. There are two main ways to realize white light, one is the mixture of red, green and blue, and the other is the direct monomer emission of white light.

At present, the external quantum efficiency of red and green perovskite light emitting diodes exceeds 20%, the blue light efficiency is low but close to 10%, and the research on the real electro-white light is very little, so that the development of high-efficiency white light emitting diodes becomes the current research hotspot. A single material with efficient and stable white light emission is most desirable for illumination, but it is difficult to achieve photon emission that covers the entire visible spectrum. Recently, the exciton self-trapping mechanism of perovskite provides possibility for realizing white light emission of monomer, and is a hot spot of current research, and the self-trapping behavior requires strong coupling between exciton (or carrier) and lattice distortion, so that white light emission with wide spectrum is shown.

Disclosure of Invention

In order to solve the technical problems, the invention provides CsPbI₃The mixed phase perovskite film and the controllable preparation method thereof have the following specific technical scheme:

controllable preparation CsPbI₃The method for preparing the mixed phase perovskite thin film comprises the following operation steps:

step 1: adding octadecene, oleylamine, oleic acid and lead iodide into a three-neck flask, heating and stirring at 140-180 ℃ under a vacuum condition to serve as a reaction solvent;

step 2: dissolving cesium stearate and oleic acid in octadecene to form a precursor solution;

and step 3: quickly injecting the precursor solution into a reaction solvent, quickly cooling by water, growing the quantum dot nuclei, and then centrifugally purifying to remove redundant long-chain organic ligands on the surfaces of the quantum dots so as to promote the transport of current carriers, namely the perovskite CsPbI is prepared₃Quantum dots;

and 4, step 4: perovskite CsPbI₃Quantum dots are dispersed in a solvent to obtain CsPbI₃Dispersing liquid of quantum dots, CsPbI₃Spin coating the quantum dot dispersion on the surface of a clean glass sheet, and heat treating in atmospheric environment, CsPbI₃The black phase can change phase under the action of water and oxygen, part of the black phase can be converted into yellow phase, and CsPbI is obtained by controlling the temperature and the time₃The mixed phase perovskite thin film has large contact surface area of the black phase and the yellow phase, so that the mixed phase thin film well combines the excellent photoelectric property and carrier transport property of the black phase and the wide spectrum of the yellow phase, meanwhile, the black phase effectively supplements the red spectrum part, and the two phases are cooperatively matched to realize the spectrum coverage of the whole visible light and obtain the emission of the white light of the monomer.

Furthermore, the volume ratio of oleic acid to octadecene in the reaction solvent prepared in the step 1 is 1: 10-20, the molar ratio of oleic acid to lead iodide is 1: 1-2, and the volume ratio of oleic acid to oleylamine is 1: 1-2.

Furthermore, the volume ratio of oleic acid to octadecene in the precursor solution prepared in the step 2 is 1: 10-20, and the molar ratio of oleic acid to cesium stearate is 1: 1-2.

Further, the stirring speed in the step 1 is 600-800 r/min.

Further, the volume ratio of the precursor solution to the reaction solvent in the step 3 is 1: 10-20.

Further, the centrifugal purification process in step 3 is as follows: dissolving the water-cooled precursor solution and the reaction solvent mixed solution into a flocculating agent, stirring and mixing uniformly, then placing the flocculating agent on a centrifuge for centrifugation, attaching the precipitate to the side wall after centrifugation, and pouring out the solution to obtain the precipitate, namely the perovskite CsPbI₃The flocculant is methanol, isopropanol, acetone, n-butanol or tert-butanol.

Further, the solvent in the step 4 is selected from n-octane, n-hexane or toluene, CsPbI₃The concentration of the dispersion of quantum dots was 15 mg/mL.

Further, CsPbI in the step 4₃In the preparation of the quantum dot dispersion, a solvent is added to the precipitate of step 3 and stirred until the precipitate is completely dissolved.

Further, the relative humidity of the environment for heat treatment in the step 4 is 40-60%, the time for heat treatment is 20-60min, and the treatment temperature is 120-140 ℃.

CsPbI prepared by any one of the above methods₃A mixed phase perovskite thin film.

The invention has the beneficial effects that:

1) the invention uses CsPbI₃The homogeneous heterogeneous structure is obtained, the black phase and the yellow phase emit different colors and complement each other on the spectrum, so that the monomer emits white light jointly, and the material is novel;

2) the nano material prepared by the invention is based on an all-inorganic perovskite material, and is more stable than the traditional perovskite material;

3) the invention can realize CsPbI through heat treatment₃The black phase is converted into the yellow phase, the phase regulation and control are realized by regulating the temperature and the time, and the method is simple and easy to implement.

Drawings

FIG. 1 shows CsPbI prepared in example 1 of the present invention₃SEM scan of the miscible thin film,

FIG. 2 shows CsPbI prepared in example 1 of the present invention₃The XRD pattern of the mixed phase film,

FIG. 3 shows CsPbI prepared in example 1 of the present invention₃The photoluminescence spectrum of the mixed-phase film,

FIG. 4 shows CsPbI prepared in example 1 of the present invention₃Light absorption spectrum of the miscible thin film.

Detailed Description

The present invention will now be described in further detail with reference to the accompanying drawings.

The invention relates to a method for preparing perovskite CsPbI by using a high-temperature thermal injection method₃Quantum dot, spin coating on substrate to form film, and heat treating to control CsPbI under certain humidity and temperature₃Conversion of yellow and black phases to obtain CsPbI₃A method for preparing a mixed phase perovskite thin film.