CN114806561B - With SiO 2 And PbSO 4 Synthesis method of double-protection stable perovskite - Google Patents

With SiO 2 And PbSO 4 Synthesis method of double-protection stable perovskite Download PDF

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CN114806561B
CN114806561B CN202210587341.8A CN202210587341A CN114806561B CN 114806561 B CN114806561 B CN 114806561B CN 202210587341 A CN202210587341 A CN 202210587341A CN 114806561 B CN114806561 B CN 114806561B
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CN114806561A (en
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孙春
韩佳辰
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Hebei University of Technology
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/66—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing germanium, tin or lead
    • C09K11/668—Sulfates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
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Abstract

The invention relates to a silicon dioxide film with SiO 2 And PbSO 4 A method for synthesizing double-protection stable perovskite. The method comprises the following steps: dissolving cesium halide and lead halide in dimethyl sulfoxide to obtain a first solution; adding a silane coupling agent into the first solution to obtain a second solution; adding a catalyst into the second solution to obtain a third solution; stirring the third solution for 5-24 hours, and then centrifugally separating to obtain a precipitate; and (3) heating the precipitate obtained in the previous step to 350-500 ℃ and calcining for 50-80 minutes to obtain the double-protection stable perovskite. The invention does not need high temperature above 800 ℃, does not volatilize perovskite, saves resources, and simultaneously ensures that the protective layer on the surface of the synthesized product is more compact, so that the perovskite material is more stable, and the synthesized perovskite material can basically maintain the original luminous performance even in more severe environments such as strong acid and strong alkali or high temperature.

Description

With SiO 2 And PbSO 4 Synthesis method of double-protection stable perovskite
Technical Field
The invention belongs to the technical field of nano fluorescent materials, and particularly relates to a perovskite material which is obtained by double protection of perovskite by lead sulfate and silicon dioxide.
Background
The metal halide perovskite has high fluorescence quantum efficiency, adjustable band gap and narrow half-peak width, and shows good application prospect in light-emitting diodes. While perovskite efficiency has made a great breakthrough, its instability is a major obstacle impeding the development of its commercial application. The cause of perovskite instability is often associated with low formation energy, which makes them extremely susceptible to light, heat, oxygen and moisture. So far, researchers have formulated various strategies to stabilize CsPbX 3 A nanocrystal. The conventional strategy is to cover the perovskite with an inert shell, which can isolate the perovskite from moisture and oxygen, and also prevent ion migration. For example, by CsPbX 3 The stability of the polymer is improved by encapsulating the polymer into inorganic oxide, mesoporous material, polymer matrix, inorganic salt and shell. However, these enclosures can only slow down CsPbX 3 Degradation under external environmental factors is still much less stable than commercial phosphors. In general, failure of a protection policy is mainly attributable to three reasons:
(1) Housing or baseThe bulk material does not fully protect CsPbX 3 For example, in a porous matrix, the pores may be exposed and not completely isolated from moisture and oxygen;
(2) The shell or matrix material is inherently unstable, such as inorganic salts that are sensitive to moisture and oxygen;
(3) The shell or matrix material is stable and can be fully covered on CsPbX 3 On nanocrystals, e.g. inorganic oxides (SiO 2 、Al 2 O 3 、SiO 2 /Al 2 O 3 、TiO 2 、ZrO 2 ) But not of sufficient density, there are still some tiny voids, which lead to external H 2 O/O 2 Is very high.
In practice, these inorganic oxides require higher synthesis or annealing temperatures to obtain dense oxides with small amounts of porosity and better barrier properties, since their degree of densification is very dependent on the annealing temperature. Some studies have shown that high temperature anneals above 800 ℃ can close the pores of the silica, resulting in better barrier properties (Effect of alkali ions on the amorphous to crystalline phase transition of silica. J. Solid State chem.2001,161, 373-378). But at such high temperatures, csPbX is caused 3 How to achieve omnidirectional encapsulation at relatively low temperatures is a great challenge for current perovskite materials, as well as wasting energy.
Disclosure of Invention
The invention aims at overcoming the defects in the prior art and provides a silicon oxide film with SiO 2 And PbSO 4 A method for synthesizing double-protection stable perovskite. The method is an in-situ synthesis method based on perovskite quantum dots, and ensures that a silicon dioxide protection matrix is constructed in situ in a liquid-phase reactant before perovskite is formed by adding a silane coupling agent and a catalyst, and then the silicon dioxide protection matrix is calcined at the temperature of 350-500 ℃ to reduce the collapse pore space of the silicon dioxide protection matrix at high temperature and enable the protective layer to be more compact; and reacting dimethyl sulfoxide with lead in the reactant to produce lead sulfate, i.e. CsPbX 3 The nano material surface is wrapped with lead sulfate to fill up tiny pores,form tighter double package, and further synthesize stable CsPbX with double protection 3 A nanomaterial. The invention does not need high temperature above 800 ℃, does not volatilize perovskite, saves resources, and simultaneously ensures that the protective layer on the surface of the synthesized product is more compact, so that the perovskite material is more stable, and the synthesized perovskite material can basically maintain the original luminous performance even in more severe environments such as strong acid and strong alkali or high temperature.
The technical scheme of the invention is as follows:
SiO-containing material 2 And PbSO 4 A method of synthesizing a double protected stable perovskite comprising the steps of:
step 1, cesium halide and lead halide are dissolved in dimethyl sulfoxide to obtain a first solution;
wherein, the molar ratio of cesium halide to lead halide is 1:1-4:1; adding 0.5-2 mmol of lead halide into each 5mL of dimethyl sulfoxide;
step 2, adding a silane coupling agent into the first solution to obtain a second solution;
adding 0.5-2mL of silane coupling agent into each 5mL of the first solution;
step 3, dropwise adding a catalyst into the second solution, and adjusting the dosage of the catalyst to enable the pH value of the solution to be 10-12 to obtain a third solution;
step 4, stirring the third solution for 5-24 hours, and then centrifugally separating to obtain a precipitate;
and 5, heating the precipitate obtained in the previous step to 350-500 ℃ and calcining for 50-80 minutes to obtain the stable perovskite with double protection.
The lead halide in the step 1 is lead chloride, lead bromide or lead iodide; cesium halide is cesium chloride, cesium bromide or cesium iodide.
In the step 2, the silane coupling agent is tetramethyl silicate, tetraethyl silicate or tetrapropyl silicate.
In step 3, the catalyst may be ammonia water, aqueous sodium hydroxide solution, triethylamine or ethylenediamine.
In the step 4, the centrifugation speed is 6000-9000 rpm, and the centrifugation time is 2-5 minutes.
The temperature rising speed in the step 5 is 2-10 ℃/min.
The invention has the substantial characteristics that:
dimethyl sulfoxide is used as a solution to react with lead halide at high temperature to generate lead sulfate coated perovskite, and meanwhile, the perovskite is embedded into a silicon dioxide matrix in situ to form a stable perovskite material with a double protection structure.
The addition of the silane coupling agent and the catalyst ensures that the silica protection matrix is constructed in situ in the liquid phase reactant before perovskite formation; simultaneously, precipitation is generated, solid-liquid separation can be realized, and liquid is recovered; and the precipitation is more, so that the volatilization of solvent and the environmental pollution are avoided.
The method can be realized under the high temperature condition of 300-500 ℃ and the dimethyl sulfoxide environment: firstly, the collapse pore space of the silicon dioxide protection matrix is reduced at high temperature, so that the protection layer is more compact; secondly, dimethyl sulfoxide reacts with lead in the reactant at high temperature to generate lead sulfate, and small pores are filled to form tighter double packages.
The beneficial effects of the invention are as follows:
(1) By embedding perovskite in situ on its surface 2 The lead sulfate is simultaneously wrapped in the matrix to synthesize the stable perovskite material with double protection. The in-situ synthesis method ensures that the formed silicon dioxide protective layer is more compact, the lead sulfate formed in the reaction compensates for the tiny pores of the silicon dioxide protective layer, and a protective shell is added on perovskite to form double protection, so that compared with the previous research and method, the product prepared by the method has better stability. The product synthesized by the method is placed in a strong acid environment (hydrochloric acid and hydrobromic acid) for 25 days, and the quantum efficiency can still keep more than 90% of the original efficiency; placing in a strong alkali environment (ammonia water) for 25 days, wherein the quantum efficiency is kept at 90% of the original efficiency; the quantum efficiency can still keep 98% of the original efficiency in a high temperature environment of 500 ℃ for 24 hours. The stability of the product of the invention in strong acid, strong alkali and high temperature environments is better than that of the product prepared by various current preparation methods.
(2) The luminous efficiency of the inorganic perovskite quantum dot coated by the silica and the lead sulfate prepared by the invention is as high as 85%.
(3) The invention has simple operation, easy repetition and the repetition rate is more than 98 percent.
Drawings
FIG. 1 is a photograph of the silica and lead sulfate double coated perovskite powder and powder prepared in example 1 under ultraviolet lamp irradiation. Wherein fig. 1a is a photograph of a perovskite powder double coated with silica and lead sulfate; fig. 1b is a photograph of a silica and lead sulfate double coated perovskite powder under uv lamp irradiation.
Fig. 2 is a photoluminescence spectrum of the silica and lead sulfate double coated perovskite powder prepared in example 1.
Fig. 3 is a graph showing the quantum efficiency of the silica and lead sulfate double coated perovskite powder prepared in example 1 in hydrochloric acid at a concentration of 36% -38% and hydrobromic acid at a concentration of 33% over time.
FIG. 4 is a graph of photoluminescent intensity over time of the silica and lead sulfate double coated perovskite powder prepared in example 1 in 28% -30% strength aqueous ammonia.
Fig. 5 is a graph showing the change of luminous intensity with time at high temperature of the silica and lead sulfate double-coated perovskite powder prepared in example 1.
Detailed Description
The present invention is further described in terms of the following examples, which are given by way of illustration only, and not by way of limitation, of the present invention, and any person skilled in the art may make any modifications to the equivalent examples using the teachings disclosed above. Any simple modification or equivalent variation of the following embodiments according to the technical substance of the present invention falls within the scope of the present invention.
Example 1: .
2mmol of cesium bromide and 1mmol of lead bromide were dissolved in 5mL of dimethyl sulfoxide to obtain a clear solution. Then 1mL of tetraethyl silicate was added to the above solution, followed by dropwise addition of ammonia water (30% strength) with stirring, and the pH of the solution was adjusted to 10-12. Soon, the solution became cloudy. After stirring for 24 hours, the mixture was centrifuged at 8000rpm for 2 minutes to obtain a gelatinous solid precipitate. The precipitate was then annealed at 500 ℃ for 60 minutes (heating rate 2 ℃/min) to give a silica and lead sulfate double coated stable perovskite.
FIG. 1a is a photograph of a powder of the product of this example, showing that the powder is green, indicating that CsPbBr is included 3 The method comprises the steps of carrying out a first treatment on the surface of the FIG. 1b is a photograph of the product powder prepared in this example under irradiation of an ultraviolet lamp, showing very bright green light.
FIG. 2 shows the photoluminescence spectrum of the product powder prepared in this example under excitation by ultraviolet light at 365nm, with a fluorescence peak at 519 nm.
Fig. 3 is a graph showing the quantum efficiency of the product as a function of time, obtained by placing the product powder prepared in this example in 36% -38% hydrochloric acid and 33% hydrobromic acid, respectively, and measuring the quantum efficiency daily. From the graph, the quantum efficiency of the product after 25 days is maintained above 90% of the original efficiency, which indicates that the product is very stable in a strong acid environment.
FIG. 4 is a graph showing the relative luminescence intensity over time of the product powder prepared in this example, which was placed in 28% -30% ammonia water, the photoluminescence intensity of the product was measured every day, and compared with the original luminescence intensity. After 25 days the photoluminescence intensity was 90% of the original intensity, indicating that the product was very stable in a strong alkaline environment.
Fig. 5 is a graph of the relative luminescence intensity over time, taken out of the product powder prepared in this example, measured for its photoluminescence intensity at 4 hour intervals, by placing the product powder in a muffle furnace and heating to 500 ℃. From the graph, the luminous intensity of the product is maintained at 98% of the original intensity after 24 hours, which indicates that the product prepared by the example can be stable in a high-temperature environment of 500 ℃.
Example 2:
example 1 was repeated except that the amount of cesium bromide was changed to 1 mmol.
Example 3:
example 1 was repeated except that the amount of cesium bromide was changed to 4 mmol.
Example 4:
example 1 was repeated except that cesium bromide was changed to cesium iodide and lead bromide was changed to lead iodide. Thus, lead sulfate and silicon dioxide coated CsPbI can be obtained 3 Perovskite material.
Example 5:
example 1 was repeated except that cesium bromide was changed to cesium iodide.
Example 6:
example 1 was repeated except that lead bromide was changed to lead iodide.
Example 7:
example 1 was repeated except that cesium bromide was changed to cesium chloride and lead bromide was changed to lead chloride. Thus, csPbCl with double package of lead sulfate and silicon dioxide can be obtained 3 Perovskite material.
Example 8:
example 1 was repeated except that cesium bromide was changed to cesium chloride.
Example 9:
example 1 was repeated except that lead bromide was changed to lead chloride.
Example 10: .
Example 1 was repeated except that the amount of tetraethyl silicate was changed to 0.5 mL.
Example 11: .
Example 1 was repeated except that the amount of tetraethyl silicate was changed to 2 mL.
Example 12:
example 1 was repeated except that the aqueous ammonia was changed to an aqueous sodium hydroxide solution (28% strength), and the pH of the solution was adjusted to 10-12 by adjusting the amount of the aqueous sodium hydroxide solution.
Example 13:
the procedure of example 1 was repeated except that the aqueous ammonia was changed to triethylamine, and the pH of the solution was adjusted to 10-12 by adjusting the amount of triethylamine.
Example 14:
the procedure of example 1 was repeated except that the ammonia water was changed to ethylenediamine, and the amount of ethylenediamine was adjusted to adjust the pH of the solution to 10-12.
Example 15:
example 1 was repeated except that tetraethyl silicate was changed to tetramethyl silicate.
Example 16:
example 1 was repeated except that tetraethyl silicate was changed to tetrapropyl silicate.
Example 17:
example 1 was repeated except that the reaction temperature was changed to 400℃at 500 ℃.
Example 18:
example 1 was repeated except that the reaction temperature was changed to 350℃at 500 ℃.
Example 19:
example 1 was repeated except that the stirring time was changed to 5 hours.
Example 20:
example 1 was repeated except that the stirring time was changed to 12 hours.
Example 21:
example 1 was repeated except that the temperature rise rate was changed from 2℃per minute to 5℃per minute.
Example 22:
example 1 was repeated except that the temperature rise rate was changed from 2℃per minute to 10℃per minute.
The invention is not a matter of the known technology.

Claims (5)

1. SiO-containing material 2 And PbSO 4 The synthesis method of the double-protection stable perovskite is characterized by comprising the following steps of:
step 1, cesium halide and lead halide are dissolved in dimethyl sulfoxide to obtain a first solution;
wherein, the molar ratio of cesium halide to lead halide is 1:1-4:1; adding 0.5-2 mmol of lead halide into each 5mL of dimethyl sulfoxide;
step 2, adding a silane coupling agent into the first solution to obtain a second solution;
wherein, 0.5-2mL of silane coupling agent is added into each 5mL of the first solution;
step 3, dropwise adding a catalyst into the second solution, and adjusting the dosage of the catalyst to enable the pH value of the solution to be 10-12 to obtain a third solution;
step 4, stirring the third solution for 5-24 hours, and then centrifugally separating to obtain a precipitate;
step 5, heating the precipitate obtained in the previous step to 350-500 ℃ for calcination for 50-80 minutes to obtain the stable perovskite with double protection;
in the step 3, the catalyst is ammonia water, sodium hydroxide aqueous solution, triethylamine or ethylenediamine.
2. The process of claim 1, wherein SiO is contained 2 And PbSO 4 The synthesis method of the double-protection stable perovskite is characterized in that lead halide in the step 1 is lead chloride, lead bromide or lead iodide; cesium halide is cesium chloride, cesium bromide or cesium iodide.
3. The process of claim 1, wherein SiO is contained 2 And PbSO 4 The synthesis method of the double-protection stable perovskite is characterized in that in the step 2, the silane coupling agent is tetramethyl silicate, tetraethyl silicate or tetrapropyl silicate.
4. The process of claim 1, wherein SiO is contained 2 And PbSO 4 The synthesis method of the double-protection stable perovskite is characterized in that the centrifugation speed in the step 4 is 6000-9000 rpm, and the centrifugation time is 2-5 minutes.
5. The process of claim 1, wherein SiO is contained 2 And PbSO 4 The synthesis method of the double-protection stable perovskite is characterized in that the heating rate in the step 5 is 2-10 ℃/min.
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