Zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength, preparation method thereof and light-emitting wavelength regulating method
阅读说明：本技术 一种发光波长可调谐的零维钙钛矿纳米晶材料、其制备方法及发光波长调控方法 (Zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength, preparation method thereof and light-emitting wavelength regulating method ) 是由 孟宪赓 石信民 张炜光 孙逊 于 2021-07-01 设计创作，主要内容包括：本发明提供一种发光波长可调谐的零维钙钛矿纳米晶材料、其制备方法及发光波长调控方法。所述制备方法包括步骤：将CTAB和DMSO混合得到前驱体溶液；将CsBr和PbBr-2分别溶于前驱体溶液中,得到CsBr-CTAB-DMSO溶液以及PbBr-2-CTAB-DMSO溶液；将两种溶液混合,加入反溶剂二氯甲烷得混合液,混合液中CsBr和PbBr-2总摩尔与CTAB的摩尔比为0.0685-17:1；搅拌条件下、40-70℃下反应12-24h；然后经析晶、洗涤、干燥得到零维钙钛矿纳米晶材料。本发明制备以及调控方法简单,成本低；所制备纳米晶材料的发光波长实现了从450nm到517nm的连续调控。(The invention provides a zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength, a preparation method thereof and a light-emitting wavelength regulating method. The preparation method comprises the following steps: mixing CTAB and DMSO to obtain a precursor solution; reacting CsBr and PbBr 2 Respectively dissolved in the precursor solution to obtain CsBr-CTAB-DMSO solution and PbBr 2 -CTAB-DMSO solution; mixing the two solutions, adding antisolvent dichloromethane to obtain mixed solution, and adding CsBr and PbBr in the mixed solution 2 The molar ratio of the total moles to CTAB is 0.0685-17: 1; reacting for 12-24h at 40-70 ℃ under the condition of stirring; then obtaining the zero-dimensional perovskite nanocrystalline material through crystallization, washing and drying. The preparation and regulation method is simple and has low cost; the luminescent wavelength of the prepared nanocrystalline material realizes the continuous regulation and control from 450nm to 517 nm.)
1. The zero-dimensional perovskite nanocrystalline material with tunable light emitting wavelength is characterized in that the nanocrystalline material is zero-dimensional lead-based halide perovskite Cs4PbBr6The micro-morphology of the nano-crystal is a hexahedron with the side length of 200-600 nm.
2. The zero-dimensional perovskite nanocrystalline material with tunable emission wavelength according to claim 1, wherein the nanocrystalline material has a tunable emission wavelength; preferably, the luminescence wavelength of the nanocrystalline material can be continuously regulated and controlled from 450nm to 517 nm.
3. A method for preparing a zero-dimensional perovskite nanocrystalline material with tunable luminescence wavelength as claimed in any one of claims 1 or 2, comprising the steps of:
(1) mixing CTAB and DMSO (dimethyl sulfoxide) to obtain a precursor solution;
(2) reacting CsBr and PbBr2Respectively dissolved in the precursor solution to obtain CsBr-CTAB-DMSO solution and PbBr2-CTAB-DMSO solution;
(3) CsBr-CTAB-DMSO solution and PbBr2Mixing the-CTAB-DMSO solution, adding an anti-solvent dichloromethane to obtain a mixed solution, and adding CsBr and PbBr in the mixed solution2The molar ratio of the total moles to CTAB is 0.0685-17: 1; reacting for 12-24h at 40-70 ℃ under the condition of stirring; then obtaining the zero-dimensional perovskite nanocrystalline material through crystallization, washing and drying.
4. The method for preparing the zero-dimensional perovskite nanocrystalline material with the tunable luminescence wavelength as claimed in claim 3, wherein in the precursor solution of the step (1), the concentration of CTAB is 2-500 mmol/L; preferably, the concentration of CTAB is 2mmol/L, 7.5mmol/L, 25mmol/L, 100mmol/L, 200mmol/L, 400mmol/L or 500 mmol/L.
5. The preparation method of the zero-dimensional perovskite nanocrystalline material with the tunable luminescence wavelength as claimed in claim 3, wherein in the step (2), the CsBr concentration in the CsBr-CTAB-DMSO solution is 0.04-0.07mol/L, preferably 0.05-0.06 mol/L; PbBr2-PbBr in CTAB-DMSO solution2The concentration of (B) is 0.01-0.02mol/L, preferably 0.0125 mol/L.
6. The method for preparing the zero-dimensional perovskite nanocrystalline material with tunable luminescence wavelength according to claim 3The preparation method is characterized in that in the step (3), CsBr and PbBr are added in CsBr-CTAB-DMSO solution2-PbBr in CTAB-DMSO solution2Is 4.5: 1.
7. The method for preparing the zero-dimensional perovskite nanocrystalline material with the tunable light-emitting wavelength according to claim 3, wherein in the mixed solution in the step (3), the volume ratio of the anti-solvent dichloromethane and DMSO is 1:25-35, preferably 1: 30.
8. The method for preparing the zero-dimensional perovskite nanocrystalline material with tunable luminescence wavelength according to claim 3, wherein the step (3) comprises one or more of the following conditions:
i. the crystallization is to add dichloromethane into the reaction solution to precipitate the nanocrystal;
ii. The washing is washing with dichloromethane;
and iii, the prepared zero-dimensional perovskite nanocrystalline material needs to be stored in isopropanol.
9. The method for preparing zero-dimensional perovskite nanocrystalline material with tunable luminescence wavelength as claimed in claim 3, wherein the amount of CTAB is changed, i.e. the mole of CTAB, CsBr and PbBr are changed2The total molar ratio realizes the regulation and control of the luminescent wavelength of the zero-dimensional perovskite nanocrystalline material.
10. The method for regulating and controlling the light-emitting wavelength of the zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength as claimed in any one of claims 1 or 2, comprising the steps of:
(1) mixing CTAB and DMSO (dimethyl sulfoxide) to obtain a precursor solution;
(2) reacting CsBr and PbBr2Respectively dissolved in the precursor solution to obtain CsBr-CTAB-DMSO solution and PbBr2-CTAB-DMSO solution;
(3) CsBr-CTAB-DMSO solution and PbBr2Mixing a CTAB-DMSO solution, and adding an anti-solvent dichloromethane to obtain a mixed solution; reacting for 12-24h at 40-70 ℃ under the condition of stirring; then carrying out crystallization,Washing and drying to obtain a zero-dimensional perovskite nanocrystalline material; CsBr and PbBr in mixed solution2The molar ratio of total moles to CTAB is 0.0685-17:1, varying the CsBr and PbBr within this range2The molar ratio of the total mole to CTAB, thereby realizing the regulation and control of the luminescent wavelength of the zero-dimensional perovskite nanocrystalline material.
Technical Field
The invention relates to a zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength, a preparation method thereof and a light-emitting wavelength regulating method, and belongs to the technical field of photoelectric materials.
Background
The metal halide perovskite material has excellent photoelectric response characteristics, has attracted extensive research attention in recent years, and has been widely applied to the fields of photovoltaics, displays, solar cells, lasers and the like.
At present, most of domestic and foreign research focuses on perovskite materials (referred to as three-dimensional perovskites for short) with structural units arranged periodically in three-dimensional scale, but the film form or the block material of the three-dimensional perovskite material usually has a serious fluorescence quenching phenomenon, thereby further influencing the further application of the three-dimensional perovskite material. In recent years, it has been found that low-dimensional perovskite materials, such as zero-dimensional perovskite Cs, can overcome the above problems4PbBr6The material can emit strong green light, and the fluorescence quantum yield of the block material can reach 60 percent, so that the material has good application prospect in the fields of micro-nano laser, LED, solar condenser and the like.
In addition, perovskites are attracting attention as optoelectronic materials that have tunable band gaps, i.e., they can realize light emission adjustment from the ultraviolet to near-infrared region by simple ion exchange, i.e., by changing the type of halide. In the current research process, the optical band gap adjusting method aiming at the perovskite is mainly a method utilizing quantum size effect and anion exchange. But due to zero-dimensional perovskite Cs4PbBr6The strong quantum confinement effect brought by the high exciton binding energy of the quantum confinement effect makes the method for adjusting the optical band gap by using the quantum size effect and further adjusting the luminescence infeasible. In addition, the current zero-dimensional perovskite Cs4PbBr6The mechanism of luminescence is not yet clear, so that it is not feasible to adjust the luminescence wavelength by anion exchange.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength, a preparation method thereof and a light-emitting wavelength regulating method. The preparation and regulation method is simple and has low cost; the luminescent wavelength of the prepared nanocrystalline material realizes the continuous regulation and control from 450nm to 517 nm.
The technical scheme of the invention is as follows:
a zero-dimensional perovskite nanocrystalline material with tunable light emitting wavelength is a zero-dimensional lead-based halide perovskite Cs4PbBr6Nanocrystals, microscopic forms thereofThe appearance is a hexahedron with the side length of 200-600 nm.
According to the invention, the light-emitting wavelength of the nanocrystalline material can be regulated; preferably, the luminescence wavelength of the nanocrystalline material can be continuously regulated and controlled from 450nm to 517 nm.
The preparation method of the zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength comprises the following steps:
(1) mixing CTAB (cetyl trimethyl ammonium bromide) and DMSO (dimethyl sulfoxide) to obtain a precursor solution;
(2) reacting CsBr and PbBr2Respectively dissolved in the precursor solution to obtain CsBr-CTAB-DMSO solution and PbBr2-CTAB-DMSO solution;
(3) CsBr-CTAB-DMSO solution and PbBr2Mixing the-CTAB-DMSO solution, adding an anti-solvent dichloromethane to obtain a mixed solution, and adding CsBr and PbBr in the mixed solution2The molar ratio of the total moles to CTAB is 0.0685-17: 1; reacting for 12-24h at 40-70 ℃ under the condition of stirring; then obtaining the zero-dimensional perovskite nanocrystalline material through crystallization, washing and drying.
Preferably, according to the invention, in the precursor solution in the step (1), the concentration of CTAB is 2-500 mmol/L; preferably, the concentration of CTAB is 2mmol/L, 7.5mmol/L, 25mmol/L, 100mmol/L, 200mmol/L, 400mmol/L or 500 mmol/L.
Preferably, in the step (2), the CsBr concentration in the CsBr-CTAB-DMSO solution is 0.04-0.07mol/L, and preferably 0.05-0.06 mol/L; PbBr2-PbBr in CTAB-DMSO solution2The concentration of (B) is 0.01-0.02mol/L, preferably 0.0125 mol/L.
Preferably, in step (3), CsBr and PbBr are present in a CsBr-CTAB-DMSO solution2-PbBr in CTAB-DMSO solution2Is 4.5: 1.
According to the invention, the volume ratio of the anti-solvent dichloromethane and DMSO in the mixed solution in the step (3) is 1:25-35, preferably 1: 30.
Preferably, in the step (3), the nanocrystal deposition is performed by adding dichloromethane to the reaction solution to deposit the nanocrystal.
Preferably, according to the present invention, in the step (3), the washing is washing with dichloromethane.
Preferably, in step (3), the prepared zero-dimensional perovskite nanocrystalline material needs to be stored in isopropanol.
According to the invention, preferably, the amount of CTAB is varied, i.e. the molar ratio of CTAB to CsBr and PbBr is varied2The total molar ratio realizes the regulation and control of the luminescent wavelength of the zero-dimensional perovskite nanocrystalline material.
The method for regulating and controlling the light-emitting wavelength of the zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength comprises the following steps:
(1) mixing CTAB and DMSO (dimethyl sulfoxide) to obtain a precursor solution;
(2) reacting CsBr and PbBr2Respectively dissolved in the precursor solution to obtain CsBr-CTAB-DMSO solution and PbBr2-CTAB-DMSO solution;
(3) CsBr-CTAB-DMSO solution and PbBr2Mixing a CTAB-DMSO solution, and adding an anti-solvent dichloromethane to obtain a mixed solution; reacting for 12-24h at 40-70 ℃ under the condition of stirring; then carrying out crystallization, washing and drying to obtain a zero-dimensional perovskite nanocrystalline material; CsBr and PbBr in mixed solution2The molar ratio of total moles to CTAB is 0.0685-17:1, varying the CsBr and PbBr within this range2The molar ratio of the total mole to CTAB, thereby realizing the regulation and control of the luminescent wavelength of the zero-dimensional perovskite nanocrystalline material.
The principle of the invention is as follows:
the invention is realized by adding the zero-dimensional perovskite Cs4PbBr6CTAB with a certain concentration is added in the generation process, the CTAB in the reaction system provides Br ions for creating a Br-rich environment, and excessive Br can generate Cs in the growth process4PbBr6Generates extrusion, thereby further regulating the zero-dimensional perovskite Cs4PbBr6The optical band gap of the perovskite reaches the adjustment of the zero-dimensional perovskite Cs4PbBr6The purpose of the emission wavelength; by changing the concentration of CTAB in the reaction system, zero-dimensional perovskite Cs can be realized4PbBr6The continuous regulation and control of the optical band gap finally achieve the continuous regulation of the zero-dimensional perovskite Cs4PbBr6The order of the wavelength of the emitted lightIn (1).
The invention has the following functions:
in the reaction process, two polar solvents, namely dimethyl sulfoxide and dichloromethane solution, create a reaction environment for the growth of the perovskite, and the perovskite is more inclined to grow at an interface with larger difference of the polarity of the solution; the specific proportion of the two polar solvents is beneficial to preparing the nanocrystalline with the specific morphology and inhibiting CsPbBr3The high-purity zero-dimensional perovskite nanocrystalline is prepared, and the regulation and control of the nanocrystalline band gap can be favorably realized, so that the regulation and control of the nanocrystalline luminescence wavelength can be realized. CTAB with a specific dosage is regulated and controlled to obtain the nanocrystalline with a specific morphology; another main aspect is Cs4PbBr6The growth creates an environment rich in Br, the excess Br-The generated perovskite topological network is distorted, so that Cs is generated4PbBr6The unit cell volume changes to regulate and control the band gap; on the other hand, the addition of CTAB with specific dosage can inhibit CsPbBr3Is generated. The invention CsBr and PbBr2Is favorable for inhibiting CsPbBr3Is generated. The proper reaction temperature, reaction time, reaction solvent and CTAB with specific dosage are beneficial to obtaining the nanocrystalline with the specific morphology. If the reaction time is too long, the obtained nanocrystals have large sizes and are non-uniform in size. The reaction is carried out under the stirring condition, the solidification of high-concentration CTAB in a reaction system is inhibited, the preparation of the nanocrystalline with the specific morphology is facilitated, and the regulation of the nanocrystalline band gap and the regulation of the nanocrystalline luminescence wavelength are favorably and smoothly realized. In a word, all steps, raw materials, conditions and the like of the method are taken as a whole, the preparation of the zero-dimensional perovskite nanocrystalline material with the specific morphology is realized under the combined action, and the regulation and control of the nanocrystalline band gap are realized under the combined action, so that the regulation and control of the nanocrystalline luminescence wavelength are realized.
The invention has the beneficial effects that:
1. the microstructure of the zero-dimensional perovskite nanocrystalline prepared by the method is a hexahedron with the side length of 200-400 nm. The preparation method and the light-emitting wavelength regulation method are simple,the cost is low; by using only zero-dimensional perovskite Cs4PbBr6The intrinsic halogen Br of the nanocrystalline ensures the zero-dimensional perovskite Cs4PbBr6The change of the self-luminescence wavelength of the nanocrystal is controlled while the phase is pure.
2. The invention aims at the current zero-dimensional perovskite Cs4PbBr6The control of nanocrystalline luminescence is still blank, the improvement is carried out on the basis of the original reverse microemulsion experimental method, Br element contained in CTAB is used to create a Br-rich environment, and CTAB and Cs with different concentrations are added in the experimental reaction process4PbBr6The unit cell volume of the nanocrystal is changed, so that the optical band gap is changed, and the regulation and control of the luminescence wavelength of the nanocrystal are realized. The luminescent wavelength of the prepared nanocrystalline material realizes the continuous regulation and control from 450nm to 517 nm.
Drawings
FIG. 1 is a scanning electron microscope image of zero-dimensional perovskite nanocrystals prepared in examples 1-7 and comparative example 2 at different CTAB concentrations.
FIG. 2 is photoluminescence and absorption spectra of zero-dimensional perovskite nanocrystals prepared in examples 1-7 at different CTAB concentrations.
FIG. 3 is a graph showing the volume change of the zero-dimensional perovskite nanocrystalline crystal cells prepared in examples 1-7 at different CTAB concentrations.
Fig. 4 is an X-ray diffraction pattern of the zero-dimensional perovskite nanocrystals prepared in example 6 and comparative example 2.
Detailed Description
The present invention will be further described with reference to the following drawings and detailed description, but is not limited thereto.
The experimental methods used in the examples are all conventional methods unless otherwise specified.
The materials, reagents and the like used in the examples are commercially available unless otherwise specified.
Example 1
A preparation method of a zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength comprises the following steps:
to 20ml of DMSO solution was added 3.640g of CTABAnd preparing 500mM CTAB-DMSO precursor solution, and preparing two parts. 0.02394g of CsBr and 0.0918g of PbBr were then added to the precursor solutions220ml of 0.056M CsBr-CTAB-DMSO solution and 20ml of 0.0125M PbBr are prepared2CTAB-DMSO solution. Then 15ml of 0.056M CsBr-CTAB-DMSO solution and 15ml of 0.0125M PbBr were added2Injecting a CTAB-DMSO solution into a long-neck flask placed in a water bath kettle, adding 1ml of an anti-solvent dichloromethane solution, and reacting for 24 hours at 45 ℃ by magnetic stirring; then 10ml of dichloromethane was added to produce Cs4PbBr6And (4) precipitating the nano-crystals. Repeatedly washing the obtained Cs with dichloromethane solution4PbBr6And (4) storing the nanocrystals in isopropanol.
Example 2
A preparation method of a zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength comprises the following steps:
adding 2.970g CTAB into 20ml of DMSO solution to prepare a CTAB-DMSO precursor solution with the concentration of 400mM, and preparing two parts; 0.02394g of CsBr and 0.0918g of PbBr were then added to the precursor solutions220ml of 0.056M CsBr-CTAB-DMSO solution and 20ml of 0.0125M PbBr are prepared2CTAB-DMSO solution. Then 15ml of 0.056M CsBr-CTAB-DMSO solution and 15ml of 0.0125M PbBr were added2Injecting a CTAB-DMSO solution into a long-neck flask placed in a water bath kettle, adding 1ml of an anti-solvent dichloromethane solution, and reacting for 24 hours at 45 ℃ by magnetic stirring; then 10ml of dichloromethane solution is added to produce Cs4PbBr6And (4) precipitating the nano-crystals. Repeatedly washing the obtained Cs with dichloromethane solution4PbBr6And (4) storing the nanocrystals in isopropanol.
Example 3
A preparation method of a zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength comprises the following steps:
to 20ml of DMSO solution was added 1.458g of CTAB prepared at 200mM concentration of CTAB-DMSO precursor solution, and the above was prepared in two portions. 0.02394g of CsBr and 0.0918g of PbBr were then added to the precursor solutions220ml of a 0.056M CsBr-CTAB-DMSO solution was prepared toAnd 20ml of 0.0125M PbBr2CTAB-DMSO solution. Then 15ml of 0.056M CsBr-CTAB-DMSO solution and 15ml of 0.0125M PbBr were added2Injecting a CTAB-DMSO solution into a long-neck flask placed in a water bath kettle, adding 1ml of an anti-solvent dichloromethane solution, and reacting for 24 hours at 45 ℃ by magnetic stirring; then 10ml of dichloromethane solution is added to produce Cs4PbBr6And (4) precipitating the nano-crystals. Repeatedly washing the obtained Cs with dichloromethane solution4PbBr6And (4) storing the nanocrystals in isopropanol.
Example 4
A preparation method of a zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength comprises the following steps:
to 20ml of DMSO solution was added 0.728g CTAB to make 100mM CTAB-DMSO precursor solution, and the solution was made up in two portions. 0.02394g of CsBr and 0.0918g of PbBr were then added to the precursor solutions2Preparing 0.056M CsBr-CTAB-DMSO solution and 0.0125M PbBr2CTAB-DMSO solution. Then 15ml of 0.056M CsBr-CTAB-DMSO solution and 15ml of 0.0125M PbBr were added2Injecting a CTAB-DMSO solution into a long-neck flask placed in a water bath kettle, adding 1ml of an anti-solvent dichloromethane solution, and reacting for 24 hours at 45 ℃ by magnetic stirring; then 10ml of dichloromethane solution is added to produce Cs4PbBr6And (4) precipitating the nano-crystals. Repeatedly washing the obtained Cs with dichloromethane solution4PbBr6And (4) storing the nanocrystals in isopropanol.
Example 5
A preparation method of a zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength comprises the following steps:
to 20ml of DMSO solution was added 0.1822g of CTAB prepared at 25mM concentration of CTAB-DMSO precursor solution, and the above was prepared in two portions. 0.02394g CsBr (0.0001mol) and 0.0918g PbBr were then added to the above precursor solutions, respectively220ml of 0.056M CsBr-CTAB-DMSO solution and 20ml of 0.0125M PbBr are prepared2CTAB-DMSO solution. Then 15ml of 0.056M CsBr-CTAB-DMSO solution and 15ml of 0.0125M PbBr were added2Injecting CTAB-DMSO solution into long-neck flask placed in water bath, and thenAdding 1ml of anti-solvent dichloromethane solution, and reacting for 24 hours under magnetic stirring at 45 ℃; then 10ml of dichloromethane was added to produce Cs4PbBr6And (4) precipitating the nano-crystals. Repeatedly washing the obtained Cs with dichloromethane solution4PbBr6And (4) storing the nanocrystals in isopropanol.
Example 6
A preparation method of a zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength comprises the following steps:
to 20ml of DMSO solution was added 0.05467g of CTAB prepared at a concentration of 7.5mM CTAB-DMSO precursor solution, and the above was prepared in two portions. 0.02394g of CsBr and 0.0918g of PbBr were then added to the precursor solutions220ml of 0.056M CsBr-CTAB-DMSO solution and 20ml of 0.0125M PbBr are prepared2CTAB-DMSO solution. Then 15ml of 0.056M CsBr-CTAB-DMSO solution and 15ml of 0.0125M PbBr were added2Injecting a CTAB-DMSO solution into a long-neck flask placed in a water bath kettle, adding 1ml of an anti-solvent dichloromethane solution, and reacting for 24 hours at 45 ℃ by magnetic stirring; then 10ml of dichloromethane was added to produce Cs4PbBr6And (4) precipitating the nano-crystals. Repeatedly washing the obtained Cs with dichloromethane solution4PbBr6And (4) storing the nanocrystals in isopropanol.
The XRD pattern of the nanocrystal prepared in this example is shown in FIG. 4, and it can be seen that Cs prepared in this example4PbBr6No three-dimensional CsPbBr in the nanocrystal3Impurities with high purity.
Example 7
A preparation method of a zero-dimensional perovskite nanocrystalline material with tunable light-emitting wavelength comprises the following steps:
to 20ml of DMSO solution was added 0.01458g of CTAB prepared at a concentration of 2mM CTAB-DMSO precursor solution, and the above was prepared in two portions. 0.02394g of CsBr and 0.0918g of PbBr were then added to the precursor solutions220ml of 0.056M CsBr-CTAB-DMSO solution and 20ml of 0.0125M PbBr are prepared2CTAB-DMSO solution. Then 15ml of 0.056M CsBr-CTAB-DMSO solution and 15ml of 0.0125M PbBr were added2-CTAB-DMSO solution injection placed in water bathAdding 1ml of anti-solvent dichloromethane solution into a long-neck flask, and reacting for 24 hours at 45 ℃ by magnetic stirring; then 10ml of dichloromethane was added to produce Cs4PbBr6And (4) precipitating the nano-crystals. Repeatedly washing the obtained Cs with dichloromethane solution4PbBr6And (4) storing the nanocrystals in isopropanol.
Comparative example 1
A preparation method of a zero-dimensional perovskite nanocrystalline material comprises the following steps:
to 20ml of DMSO solution was added 1.458g of CTAB prepared at 200mM concentration of CTAB-DMSO precursor solution, and the above was prepared in two portions. 0.02394g of CsBr and 0.0918g of PbBr were then added to the precursor solutions220ml of 0.056M CsBr-CTAB-DMSO solution and 20ml of 0.0125M PbBr are prepared2CTAB-DMSO solution. Then 5ml of 0.056M CsBr-CTAB-DMSO solution and 10ml of 0.0125M PbBr were added2Injecting a CTAB-DMSO solution into a long-neck flask placed in a water bath kettle, adding 1ml of an anti-solvent dichloromethane solution, and reacting for 24 hours at 45 ℃ by magnetic stirring; then 10ml of dichloromethane solution is added to produce Cs4PbBr6And (4) precipitating the nano-crystals. Repeatedly washing the obtained Cs with dichloromethane solution4PbBr6And (4) nanocrystals.
The analysis of XRD test shows that CsBr and PbBr are caused2The ratio is not proper, so that the obtained zero-dimensional Cs4PbBr6The nano crystal is doped with three-dimensional CsPbBr3Impurities.
Comparative example 2
A preparation method of a zero-dimensional perovskite nanocrystalline material comprises the following steps:
to two 20ml DMSO solutions were added 0.02394g CsBr and 0.0918g PbBr, respectively2Preparing 0.056M CsBr-DMSO solution and 0.0125M PbBr2-DMSO solutions. Then 15ml of 0.056M CsBr-DMSO solution and 15ml of 0.0125M PbBr were added2Injecting the DMSO solution into a long-neck flask placed in a water bath kettle, adding 1ml of anti-solvent dichloromethane solution, and reacting for 24 hours under magnetic stirring at 45 ℃; then 10ml of dichloromethane solution is added to produce Cs4PbBr6And (4) precipitating the nano-crystals. Repeated with dichloromethane solutionCs obtained by washing4PbBr6And (4) nanocrystals.
The XRD pattern of the nanocrystal obtained in the comparative example is shown in FIG. 4, and it can be seen that the zero-dimensional Cs obtained by the method4PbBr6Compared with the zero-dimensional Cs obtained by adding CTAB in the preparation process of the nanocrystalline4PbBr6The nanocrystal can generate CsPbBr more easily3Impurities.
Test examples
1. SEM images of the zero-dimensional perovskite nanocrystalline materials prepared in example 1(CTAB concentration of 0.5M), example 2(CTAB concentration of 0.4M), example 3(CTAB concentration of 0.2M), example 4(CTAB concentration of 0.1M), example 5(CTAB concentration of 25mM), example 6(CTAB concentration of 7.5mM), example 7(CTAB concentration of 2mM) and comparative example 2(CTAB concentration of 0mM) are shown in FIG. 1, and it can be seen from the SEM images that the prepared nanocrystalline material Cs is4PbBr6The micro-morphology of the material is hexahedron, and the side length is 200nm-600 nm.
2. The optical absorption and photoluminescence spectra of the zero-dimensional perovskite nanocrystalline materials prepared in examples 1-7 are shown in FIG. 2, wherein the dotted line is the optical absorption spectrum and the solid line is the photoluminescence spectrum, and it can be seen from the figure that the zero-dimensional perovskite Cs4PbBr6By growing in CTAB reaction environment with different concentrations, the optical band gap of the crystal changes, resulting in zero-dimensional perovskite Cs4PbBr6The wavelength of the emitted light is changed. The luminescent wavelength of the prepared nanocrystalline material can be continuously regulated and controlled from 450nm to 517 nm.
3. The unit cell volumes of the zero-dimensional perovskite nanocrystalline materials prepared in examples 1-7 are shown in fig. 3, and it can be seen from the figure that the unit cell volumes are continuously reduced along with the increase of CTAB concentration, and the reduction of optical band gap is driven to promote the blue shift of the luminescence wavelength of the nanocrystals.