阅读说明：本技术 具有高偏振特性的高度有序钙钛矿纳米片薄膜及制备方法 (Highly ordered perovskite nanosheet film with high polarization characteristic and preparation method thereof ) 是由 杨丹丹 李晓明 曾海波 于 2020-04-30 设计创作，主要内容包括：本发明公开了一种具有高偏振特性的高度有序钙钛矿纳米片薄膜及制备方法,属于无机半导体发光材料技术领域。其步骤为：在惰性气体条件下,将溴化铅,4-十二烷基苯磺酸,十八烯和油胺依次加入反应容器中,脱气,搅拌加热至一定温度后,继续升高温度依次注入一定量的油酸和油胺溶液,形成透明的前驱体溶液；将油酸铯前驱体溶液缓慢加入该前驱体溶液中,反应一段时间后快速降温,得到无机卤素钙钛矿纳米片溶液；将乙酸乙酯加入钙钛矿纳米片溶液中进行提纯,离心除去上清液,收集钙钛矿纳米片的己烷溶液；将所得高度有序钙钛矿纳米片的己烷溶液在二氧化钛基片上提拉成膜,即得高偏振特性的钙钛矿纳米片薄膜。本发明利用晶面诱导配位竞争策略精确控制钙钛矿纳米片的生长取向,制备出高度有序的钙钛矿纳米片。(The invention discloses a highly ordered perovskite nanosheet film with high polarization characteristics and a preparation method thereof, and belongs to the technical field of inorganic semiconductor luminescent materials. The method comprises the following steps: under the condition of inert gas, sequentially adding lead bromide, 4-dodecylbenzene sulfonic acid, octadecene and oleylamine into a reaction container, degassing, stirring and heating to a certain temperature, continuously raising the temperature, and sequentially injecting a certain amount of oleic acid and oleylamine solution to form a transparent precursor solution; slowly adding the cesium oleate precursor solution into the precursor solution, reacting for a period of time, and then rapidly cooling to obtain an inorganic halogen perovskite nanosheet solution; adding ethyl acetate into the perovskite nanosheet solution for purification, centrifuging to remove supernatant, and collecting the hexane solution of the perovskite nanosheets; and drawing the obtained hexane solution of the highly-ordered perovskite nano sheet on a titanium dioxide substrate to form a film, thus obtaining the perovskite nano sheet film with high polarization characteristic. According to the invention, the growth orientation of the perovskite nanosheet is accurately controlled by using a crystal face induced coordination competition strategy, so that the highly ordered perovskite nanosheet is prepared.)

1. A preparation method of a highly ordered perovskite nanosheet film with high polarization characteristic is characterized by comprising the following steps:

step one, sequentially adding lead bromide, 4-dodecylbenzene sulfonic acid, octadecene and oleylamine (a) into a reaction vessel under the condition of inert gas, degassing, stirring and heating to 100-125%^oC; continuously raising the temperature to 145-165 DEG C^oC, injecting a certain amount of oleic acid (b); continuously rising to 170-185 DEG C^oC, injecting a certain amount of oleylamine (C) to obtain a precursor solution;

slowly adding a cesium oleate precursor solution into the precursor solution obtained in the step one, reacting for a period of time, and rapidly cooling to obtain an inorganic halogen perovskite nanosheet solution;

step three, adding ethyl acetate into the perovskite nanosheet solution obtained in the step two for purification, centrifuging to remove supernatant, dispersing the obtained precipitate into hexane, and centrifuging to collect the hexane solution of the highly ordered perovskite nanosheets;

and step four, drawing the hexane solution of the perovskite nano sheet obtained in the step three on a titanium dioxide substrate at a certain speed to form a film, and obtaining the perovskite nano sheet film.

2. The method of claim 1, wherein oleylamine (a), oleic acid (b), and oleylamine (c) are added in a volume ratio of 3 to 2: 3: 0 to 1.

3. The method of claim 1, wherein the lead bromide to oleic acid is added in a ratio of 0.2 g: 3 ml.

4. The method of claim 1, wherein the molar ratio of lead bromide, octadecene, 1, 4-dodecylbenzenesulfonic acid, cesium oleate is 0.54: 46.93: 4-4.58: 0.068.

5. the method of claim 1, wherein in the second step, the reaction time is 20-40 s, and the cooling temperature is 30-40 s^oC。

6. The method according to claim 1, wherein in the third step, the centrifugal speed when the supernatant is removed by centrifugation is 7000-9000 r/min, and the centrifugal speed when the hexane solution of the perovskite nano-sheets is collected by centrifugation is 5000-8000 r/min.

7. The method of claim 1, wherein in step four, the pulling rate is 1000 to 3000 μm/s.

8. The method of claim 1, wherein the cesium oleate precursor solution is prepared by the steps of: adding cesium carbonate, oleic acid and octadecene into a reaction container together under the condition of argon, exhausting and heating until the cesium carbonate is completely dissolved, and cooling to obtain a cesium oleate precursor solution when the reaction temperature is stable.

9. A highly ordered perovskite nanoplate thin film with high polarization characteristics prepared by the method as claimed in any one of claims 1 to 8.

Technical Field

The invention belongs to the technical field of preparation of inorganic semiconductor luminescent materials, and particularly relates to a highly-ordered perovskite nanosheet film with high polarization characteristics and a preparation method thereof.

Background

In recent years, halogen perovskite nanocrystals APbX₃(wherein A is methylamine, formamidine, cesium, etc., and X is halogen) has attracted extensive attention due to its high quantum efficiency (80% -95%), narrow emission, high carrier migration rate, wide color gamut, etc. In addition, the halogen perovskite nanocrystalline also has the polarization luminescence characteristic and is expected to be applied to the fields of polarization sensitive detectors, visible light communication and the like. However, as a soft lattice ionic semiconductor material, the nucleation growth rate of the halogen perovskite nanocrystal is much higher than that of other nanocrystal materials, which causes the morphology and size of the perovskite nanocrystal to be difficult to control, and is not beneficial to realizing anisotropic controllable growth.

In order to solve this problem, one-dimensional or two-dimensional perovskite materials having anisotropy have attracted extensive attention of researchers due to their excellent optical and polarization characteristics. For example, the synthesis of perovskite nanorods relies primarily on Cs at the water-oil interface₄PbBr₆Opposite CsPbBr₃Phase inversion is carried out, and the directional growth of the crystal is controlled. However, this synthesis inevitably introduces water molecules, which destroy the stability of perovskite nanocrystals (j. mater. chem. C, 2019.7 (24), 7201-. In addition, Shanghai university Yangyouyong team seed intermediate in (OAm)₃And TDP ligand is added into the precursor solution to promote the perovskite nanocrystal to be converted into the nanorod. The synthesis of this system readily forms Cs₃In₂Br₉And CsPb₂Br₅Heterogeneous phase, and complicated process and uncontrollable size (Nano Letters 2019, 19 (9), 6315-. Based on this, these two strategies are disadvantageous for the subsequent study of the polarization properties of perovskite nanocrystals. Recently, 10.8 and 23.2 nm nanorods were synthesized by the Andrey L.Rogach team, university of hong Kong City, and the longest single nanorod luminescence polarization degree was measured to be 2.0 (ACS Nano, 2019.13 (7), 8237-8245). However, the synthesized nanorods have a fluorescence quantum efficiency of only 60% to 70%, and cannot satisfy the conditions for preparing efficient and highly polarizing films. Therefore, a size-controllable and high-volume product is developedPerovskite nano-sheet with sub-efficiency and high polarization characteristic, CsPbBr capable of realizing high spectral conversion efficiency₃The nanosheet film is applied to polarization enhanced imaging.

Disclosure of Invention

The invention aims to provide a highly-ordered perovskite nanosheet film with high polarization characteristics and a preparation method thereof.

The invention adopts the following technical scheme:

a highly ordered perovskite nanosheet film with high polarization characteristics and a preparation method thereof comprise the following steps:

step one, preparing a cesium oleate precursor solution: adding cesium carbonate, oleic acid and octadecene into a reaction container together under the condition of argon, exhausting and heating until the cesium carbonate is completely dissolved, and cooling to obtain a cesium oleate precursor solution when the reaction temperature is stable;

step two, sequentially adding lead bromide, 4-dodecylbenzene sulfonic acid, octadecene and oleylamine (a) into a reaction vessel under the condition of inert gas, degassing, stirring and heating to 100-125%^oC; continuously raising the temperature to 145-165 DEG C^oC, injecting a certain amount of oleic acid (b); continuously rising to 170-185 DEG C^oC, injecting a certain amount of oleylamine (C) to finally form a transparent precursor solution;

step three, slowly adding the cesium oleate precursor solution obtained in the step one into the precursor solution obtained in the step two, reacting for a period of time, and then rapidly cooling to obtain an inorganic halogen perovskite nanosheet solution;

step four, adding ethyl acetate into the perovskite nanosheet solution obtained in the step three for purification, centrifuging to remove supernatant, dispersing the obtained precipitate into hexane, and centrifuging to collect the hexane solution of the highly ordered perovskite nanosheets;

and step five, drawing the hexane solution of the perovskite nanosheets obtained in the step four on a titanium dioxide substrate at a certain speed to form a film, and obtaining the perovskite nanosheet film with high polarization characteristic.

Further, in the first step, the molar ratio of cesium carbonate, oleic acid and octadecene is 1.15: 4.73: 47.3.

further, in the first step, heating to 100-120 ℃ after exhausting; and cooling to 60-80 ℃ in a water bath to obtain the cesium oleate precursor solution.

Further, in the second step, the volume ratio of the oleylamine (a), the oleic acid (b) and the oleylamine (c) is 3-2: 3: 0 to 1.

Further, in the second step, the adding ratio of the lead bromide to the oleic acid is 0.2 g: 3 ml.

Further, in the second step, the molar ratio of the lead bromide, the octadecene, the 1, 4-dodecylbenzene sulfonic acid and the cesium oleate is 0.54: 46.93: 4-4.58: 0.068.

further, in the third step, the reaction time is 20-40 s, and the cooling temperature is 30-40 s^oC。

Further, in the fourth step, the centrifugal speed when the supernatant is removed by centrifugation is 7000-9000 r/min, and the centrifugal speed when the hexane solution of the perovskite nano-sheets is collected by centrifugation is 5000-8000 r/min.

Furthermore, in the fifth step, the pulling speed is 1000-3000 μm/s.

Compared with the prior art, the invention has the beneficial effects that:

the method provided by the invention is simple, convenient and efficient, anisotropic growth of the perovskite nanosheet in the horizontal direction is promoted by a crystal face induced coordination competition strategy, and meanwhile, halogen vacancy defects in the nucleation process can be filled, so that the perovskite nanosheet with high quantum efficiency and high polarized light emitting characteristics is obtained.

Drawings

FIG. 1 shows CsPbBr in examples 1-2 of the present invention₃Transmission electron microscopy images of quantum dots and nanoplates.

FIG. 2 shows CsPbBr in examples 1-2 of the present invention₃Powder X-ray diffraction patterns of quantum dots and nanoplates.

FIG. 3 shows CsPbBr in examples 1-2 of the present invention₃Particle size distribution diagram of quantum dots and nano-sheets.

FIG. 4 is a transmission electron micrograph of oleylamine (a) and oleylamine (c) according to examples 3 to 5 of the present invention at different ratios.

FIG. 5 is a graph showing the particle size distribution of oleylamine (a) and oleylamine (c) at different ratios according to examples 3 to 5 of the present invention.

FIG. 6 is a powder X-ray diffraction pattern of oleylamine (a) and oleylamine (c) at different ratios according to examples 3 to 4 of the present invention.

FIG. 7 is a transmission electron microscope image of dodecylbenzene sulfonic acid in different molar amounts according to examples 6-10 of the present invention.

FIG. 8 is a graph showing the particle size distribution of dodecylbenzene sulfonic acid in different molar amounts according to examples 6 to 10 of the present invention.

FIG. 9 is a powder X-ray diffraction pattern of dodecylbenzene sulfonic acid at different molar amounts as described in examples 5-10 of the present invention.

FIG. 10 is a schematic diagram of the polarization degree of perovskite nanosheets of different lengths as described in examples 11-12 of the present invention.

Detailed Description

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