83 results about "Lead bromide" patented technology

The invention provides a stable perovskite precursor solution and a preparation method and application thereof. The perovskite precursor solution comprises a solute, a solvent and a stabilizer; the stabilizer comprises a compound containing a reducing group and a hydrogen ion group capable of being ionized; the solute comprises bromomethylamine, formamidine iodide, chloromethylamine, cesium iodide, lead iodide and lead bromide. The preparation method comprises the following steps: mixing a solute and a solvent, adding a stabilizer into the mixture, and mixing to obtain the perovskite precursor solution. According to the invention, the specific composition of the perovskite precursor solution is designed, and a specific stabilizer is further used, so that the perovskite precursor solution with relatively high stability and a relatively good storage effect is prepared.

The invention provides a preparation method of a perovskite thin film and a perovskite light-emitting diode. The method comprises the steps that lead iodide, lead bromide, a cesium iodide mixture and organic ammonium iodide salt are dissolved in a polar solvent, a perovskite precursor solution is obtained, and the cesium iodide mixture comprises cesium iodide and cesium triiodide; and dispensing the perovskite precursor solution on a substrate, enabling the substrate to rotate in an accelerated manner, and dropwise adding an anti-solvent in the rotation process to obtain the perovskite thin film. The perovskite thin film prepared by the invention is more compact and has fewer holes, meanwhile, the formation of a low-dimensional phase in the perovskite thin film is reduced, the defect density in the perovskite thin film is reduced, halogen movement is reduced, and better spectral stability and operation stability are realized while the efficiency and the brightness of a pure red light perovskite light-emitting diode are improved.

The invention discloses a cesium-lead-bromine / silicon dioxide quantum dot and a preparation method thereof, and belongs to the technical field of quantum dot luminescent materials.The preparation method comprises the steps that at the temperature of 75-95 DEG C, cesium bromide, lead bromide and water are mixed and then magnetically stirred, and a cesium-lead-bromine precursor solution is obtained; at the temperature of 75-95 DEG C, mixing aminopropyltriethoxysilane with the cesium-lead-bromine precursor solution, and then carrying out magnetic stirring to obtain a cesium-lead-bromine / silicon dioxide solution; and drying the cesium lead bromide / silicon dioxide solution at the temperature of 75-95 DEG C to obtain the cesium lead bromide / silicon dioxide quantum dots. The cesium-lead-bromine / silicon dioxide quantum dot has the characteristics of structural stability, acid resistance, 800 DEG C high temperature resistance, water resistance and the like, is long in luminescence life, high in quantum yield and non-toxic, and meets the preparation requirements of flexible wearable devices, light-emitting gratings and other optical devices.

The invention belongs to the technical field of solar cells, and particularly relates to a perovskite precursor solution containing iodine bromide. The solution is prepared by dissolving cesium iodide, lead iodide, formamidine iodide, lead bromide, formamidine bromide and iodine bromide in a mixed organic solvent. The iodine bromide can inhibit aging and deterioration of perovskite precursor solution components, and the solution stability is good.

The invention discloses a preparation method of a portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3 at-UiO-66 / Ru, which comprises the following steps: 1, adding lead bromide and cesium bromide into N, N-dimethylformamide, then adding 5-bromovaleric acid and an oleylamine ligand, and stirring; 2, perfluorooctyltriethoxysilane is added, and a precursor solution is obtained; 3, adding zirconium chloride and terephthalic acid into N, N-dimethylformamide to obtain a homogeneous solution; 4, after heating, UiO-66 is obtained; 5, stirring the precursor solution, APBA, UiO-66 and tris (2, 2-dipyridyl) ruthenium chloride hexahydrate to obtain a composite material; and 6, dropwise adding the composite material solution into the filter paper. The APBA modified material is adopted as a recognition unit, the APBA modified material and the paper base construct a fluorescence sensing platform, visual quantitative analysis of oxytetracycline in water is achieved, and the device is convenient to carry, low in detection limit, high in anti-interference performance, easy and convenient to operate and suitable for on-site rapid detection of oxytetracycline.

The present application relates to a trace neodymium doped phenethylamine lead bromide monocrystal capable of simultaneously enhancing light yield and shortening decay time and application thereof, which solves the technical problem that the prior art is difficult to simultaneously improve light yield and shorten luminescence decay time. The trace neodymium doped phenethylamine lead bromide monocrystal capable of simultaneously enhancing light yield and shortening decay time is prepared by the following steps: 1) weighing; phenethylamine hydrobromide, lead bromide and neodymium bromide are weighed and placed in a glass bottle; the molar ratio of the phenethylamine hydrobromide, lead bromide and neodymium bromide is 2:1:(0.02-0.05); 2) obtaining a precursor solution; N,N-dimethylformamide is added to the glass bottle, heated and stirred until completely dissolved to obtain a precursor solution; 3) obtaining a crystal; the precursor solution is filtered and placed in a glass beaker for crystallization to obtain a neodymium doped phenethylamine lead bromide monocrystal; through adjustment of the crystal band structure by neodymium, the radiation recombination rate is improved.

The invention discloses a preparation method of a perovskite thin film, which comprises the following steps: carrying out vapor deposition on lead bromide on the surface of a substrate to obtain a lead bromide layer; and reacting the lead bromide layer with an organic salt to obtain the perovskite thin film. According to the invention, the vapor deposition technology is adopted to prepare the lead bromide precursor layer with high crystal quality and preferred orientation; the large-size and high-orientation lead bromide crystal grains provide an ideal reaction template for organic salt permeation, the prepared perovskite thin film is more complete in reaction compared with a traditional solution method, and the crystallinity and the crystal grain size are obviously improved; in addition, according to the process, auxiliary devices such as an anti-solvent and an air knife are avoided, the process flow is simplified, the problem of uncontrollable crystallization caused by the auxiliary devices is also avoided, and the repeatability of thin film preparation is improved.

The invention relates to a preparation method of a metal halide perovskite-coated three-dimensional cobalt porphyrin-based COFs (Covalent Organic Frameworks) composite material, which comprises the following steps: S1, reacting an aldehyde precursor with an amine precursor in a first organic solvent, and after the reaction is finished, performing post-treatment to obtain a three-dimensional cobalt porphyrin-based COFs material; wherein the aldehyde precursor is 5 ', 5 '', 5'' '', 5'' ''''-(5, 10, 15, 20-tetrayl) tetra (([1, 1': 3 ', 1 ''-terphenyl]-4, 4''-diformyl))-21H, 23H-cobalt porphyrin (II), and the amine precursor is 4, 4'-diamino terphenyl and 2 ', 5'-bis ((methylthio) methyl)-[1, 1 ': 4', 1 ''-biphenyl]-4, 4''-diamine; s2, in a second organic solvent, enabling the three-dimensional cobalt porphyrin-based COFs material to react with lead bromide, and after the reaction is finished, performing post-treatment to obtain a PbBr2 (at) 3D Co-COFs material; and S3, in a third organic solvent, carrying out a reaction on the PbBr2 (at) 3D Co-COFs material and methylamine bromide, and after the reaction is finished, carrying out post-treatment to obtain the metal halide perovskite (at) three-dimensional cobalt porphyrin-based COFs composite material. The preparation method has the advantage that the photocatalytic activity and stability are improved.

The invention discloses an ultraviolet-assisted silicon-coated perovskite quantum dot and a preparation method thereof, and belongs to the technical field of nano materials, and the ultraviolet-assisted silicon-coated perovskite quantum dot is prepared from lead bromide, octadecene, oleic acid, oleylamine, silane and a cesium source through a series of operation steps. According to the ultraviolet-assisted silicon-coated perovskite quantum dot and the preparation method thereof, the required raw materials are simple, the reaction condition is mild, the reaction is rapid, the product generation efficiency is high, the prepared perovskite quantum dot is small in size, silicon coating is complete, the crystallinity is excellent, the fluorescence performance is excellent, and the stability is improved.

This invention provides a microgap suspension device and a microgap inverted suspension heat treatment process, comprising the following steps: adding p-aminobenzenesulfonic acid to a solvent, mixing thoroughly, and then adding carbon nanotubes to obtain a carbon nanotube dispersion; stirring the carbon nanotube dispersion under heating conditions to obtain a p-aminobenzenesulfonic acid-modified carbon nanotube dispersion; coating a substrate surface with a lead bromide solution, then coating the lead bromide surface with a cesium bromide solution, then coating the cesium bromide surface with the p-aminobenzenesulfonic acid-modified carbon nanotube dispersion; and finally performing heat treatment through a microgap suspension device to form a photoactive layer film. The microgap inverted suspension heat treatment process of this invention, through controllable height suspension heat treatment, ensures that the film is almost unconstrained by the rigidity of the substrate during thermal expansion and cooling contraction, thus making it suitable for flexible substrates as well. It also avoids direct contact damage to flexible substrates during high-temperature heat treatment.

The invention discloses a preparation method of a manganese-doped CsPbBr3 single crystal, and belongs to the field of inorganic perovskite preparation. The preparation method specifically comprises the following steps: dissolving cesium bromide, lead bromide and manganese bromide in a DMSO (dimethyl sulfoxide) solvent, adding bromohexanoic acid, and fully mixing in a water bath to obtain a mixed solution I; then methanol, cyclohexanol and DMF (N, N-dimethylformamide) are fully mixed, and a mixed solution II is obtained; mixing the mixed solution I and the mixed solution II, fully stirring in a water bath, and filtering by using a filter to obtain a precursor solution; and putting a seed crystal into the precursor solution, putting the precursor and the container into silicone oil, and obtaining the manganese-doped CsPbBr3 single crystal by adopting an inverse temperature crystallization method. The manganese-doped CsPbBr3 single crystal prepared by the invention has excellent photoelectric properties and stability, and can be used for low-temperature semiconductor radiation detectors.

The invention relates to a lead-based perovskite single crystal, a method for controlling growth of the lead-based perovskite single crystal and application of the lead-based perovskite single crystal, and the method for controlling growth of the lead-based perovskite single crystal comprises the following steps: dissolving bromoacetic acid in dimethyl sulfoxide, and heating, stirring and mixing to obtain a mixed solution; adding the mixed solution and a solvent into a mixture of lead chloride, methylamine bromide and lead bromide, and stirring for reaction to obtain a precursor solution; and filtering and heating the precursor solution to obtain the perovskite single crystal. In the crystal growth process, the high-quality perovskite single crystal can be obtained in a short growth period by adjusting nucleation dynamics and maintaining the stability of the growth solution, the contradiction between the growth efficiency of the single crystal and the quality of the single crystal is relieved by utilizing a nucleation inhibition strategy, and on the premise that the sensitivity of a detector is not sacrificed, the high-quality perovskite single crystal can be obtained. The crystal growth period can be effectively shortened.

The invention belongs to the field of perovskite devices, and particularly discloses a bromine-chlorine mixed blue-light perovskite thin film, a preparation method and a perovskite LED device. The bromine-chlorine mixed blue-light perovskite thin film is prepared from the following raw materials: cesium halide, lead bromide, lead chloride and alkaline earth metal bromide; the alkaline earth metal bromide comprises at least one of calcium bromide, strontium bromide and barium bromide; the ratio of the mole number of the alkaline earth metal bromide to the total mole number of Pb in lead bromide and lead chloride is not greater than 0.5. The bromine and chlorine mixed blue light perovskite is doped by adopting the alkaline earth metal bromide with a low-solubility perovskite phase, and the molar ratio of the doping amount of the alkaline earth metal bromide is not higher than 0.5, so that the nonuniform bromine and chlorine distribution of the blue light perovskite thin film in the film forming process is improved, the halogen separation under an electric field is inhibited, and the spectral stability is improved; by directly doping in the precursor, the preparation process is simple, and the method is suitable for large-scale industrial production.

This application relates to a method for preparing Mn-doped CsPbBr3 nanowires. The method comprises: 1) injecting a cesium oleate precursor solution into a mixed solution A, dispersing the resulting precipitate by centrifugation in an oil-phase solvent, and obtaining a CsPbBr3 nanowire seed solution; 2) injecting the CsPbBr3 nanowire seed solution into a mixed solution B to form Mn-doped CsPbBr3 nanowires, cooling the solution, and centrifuging the resulting precipitate. Mixed solution A is prepared by mixing octadecene, oleic acid, oleylamine, and lead bromide, heating the mixture until the lead bromide is fully dissolved, and then cooling the mixture; mixed solution B is prepared by mixing octadecene and manganese bromide and heating the mixture under an inert gas atmosphere. This method provides sufficient thermal energy for the dopant while minimizing Ostwald maturity, allowing the dopant to diffuse into the crystal without the use of highly corrosive acids. While maintaining the nanowire's shape anisotropy and overall dimensional uniformity, it can produce nanowires with ultra-small diameters, making it an effective method for synthesizing Mn-doped CsPbBr3 nanowires.

The invention discloses a growth method of an organic-inorganic hybrid two-dimensional phenylethylamine lead bromide perovskite single crystal, relates to a growth method of a phenylethylamine lead bromide perovskite single crystal, and aims to solve the technical problems of long growth period and small thickness of the existing two-dimensional phenylethylamine lead bromide single crystal. The method comprises the following steps: 1, obtaining seed crystals; 2, thermodynamically regulating and controlling the solution supersaturation degree by a constant-temperature water bath device; 3, seed crystal growth is dynamically regulated and controlled through a seed crystal rotating-gradient cooling method under the solution rotating condition, the phenylethylamine lead bromide perovskite single crystal is obtained, the length and width of the phenylethylamine lead bromide perovskite single crystal are larger than 2 cm, the thickness of the phenylethylamine lead bromide perovskite single crystal is larger than 2 mm, fast neutron detection and high-energy nuclear particle screening can be met, and the phenylethylamine lead bromide perovskite single crystal is applied to the field of nuclear radiation detectors.

The application relates to a large-size orthorhombic phase bromine lead cesium single crystal and a solution growth method and application thereof, and belongs to the technical field of crystal materials. The application comprises the following steps: (1) mixing water and dimethyl sulfoxide uniformly, adding cesium bromide and lead bromide to obtain a bromine lead cesium solution; (2) overheating the bromine lead cesium solution at 70-80 DEG C for 24-48h to obtain a bromine lead cesium growth solution; and (3) growing the bromine lead cesium seed in the bromine lead cesium growth solution or spontaneously nucleating and growing under a sealed condition to obtain a large-size orthorhombic phase bromine lead cesium single crystal. The application uses a mixed solution of water and dimethyl sulfoxide as a solvent of cesium bromide and lead bromide for the first time, lets water participate in the growth of the bromine lead cesium crystal, changes the inverse temperature crystallization property of the CsPbBr3 crystal, changes the solubility of the CsPbBr3 crystal from an inverse temperature curve into a positive temperature curve, realizes the temperature-reducing controlled growth of the crystal, and effectively avoids the generation of other by-products of the bromine lead cesium.

The application discloses an X-ray detection composite material structure and a preparation method thereof. The composite material structure is composed of a conductive substrate (ITO glass), a nickel oxide (NiOx) nanostructure, a lead bromide formamidine (MAPbBr3) single crystal and an upper electrode. The preparation method comprises batching, a liquid phase reaction method and a solution method single crystal growth. The composite material structure prepared by the application can realize self-driven X-ray detection, that is, converts incident X-rays into current signals without an external bias voltage. The application has the advantages of low detection limit, wide detection energy range, high resolution, rapid response, good linearity and low manufacturing cost, and can be applied to X-ray detection, X-ray imaging, light sensors and many other fields.

The invention discloses a method for improving the photoluminescence efficiency and stability of blue-light cesium-lead-bromine perovskite quantum dots, and belongs to the technical field of luminescent materials. According to the invention, the strong confinement CsPbBr3 quantum dot is synthesized under the condition of rich halide; then, didodecyl dimethyl ammonium bromide and lead bromide are cooperatively used for synthesis aftertreatment, and the surface-modified blue-light cesium-lead-bromine perovskite quantum dots are obtained. Through ligand modification after synthesis, a halide-rich environment is created on the surface of the CsPbBr3 quantum dot, and the vacancy defect is effectively passivated. In addition, a relatively short-chain proton-free quaternary ammonium salt ligand is adhered to the surface of the quantum dot, is bonded with an uncoordinated lead site, and is subjected to in-situ exchange with an original long-chain organic ligand on the surface of the quantum dot. Therefore, the photoluminescence quantum yield of the treated blue light CsPbBr3 perovskite quantum dot is close to 100%, and the blue light CsPbBr3 perovskite quantum dot has excellent stability.

The invention discloses a method for regulating wide-band gap perovskite crystallization through CsPb2Br5 and laminated photovoltaic application thereof, and particularly relates to the field of photoelectric materials and devices. Comprising the following steps: preparing a CsPb2Br5 nanosheet; the preparation method comprises the following steps: dissolving cesium iodide, formamidine hydriodate, lead iodide, lead bromide and CsPb2Br5 nanosheets in a solvent to obtain a perovskite precursor solution; wherein the perovskite precursor solution comprises two phases, namely a Cs0.2 FA < 0.8 > PbI < 1.8 > Br < 1.2 > perovskite precursor complex and a CsPb2Br < 5 >; and preparing the perovskite precursor solution into a perovskite thin film of the solar cell to obtain the solar cell. The crystal can be guided to uniformly grow along the vertical direction, the crystal boundary and defects are reduced, the crystal structure is optimized, and the stability and uniformity of the film are enhanced; and photo-induced halogen phase separation and defect formation can be inhibited, so that the photoelectric property and long-term stability of the perovskite thin film are improved.

A method and system for preparing perovskite caesium lead bromide, CsPbBr3, nanoparticles from a caesium oleate stock solution under a nitrogen atmosphere. The method may include the following steps: into a three-necked flask, first add octadecene (ODE), followed by sequentially adding cesium carbonate, Cs2CO3, powder and oleic acid (OA); connecting a nitrogen cylinder to one end of the three-necked flask and introducing nitrogen for 0.5-1 hour to expel the air therein. Under a nitrogen atmosphere, the solution in the flask is heated to 120°C and this temperature maintained for 1-2 hours. In an additional three-necked flask, lead bromide, PbBr2, powder may be dissolved in octadecene in a nitrogen atmosphere at 120°C and then injected with oleic acid and oleylamine solution. After heating the PbBr2 solution to 160 °C, the previously made hot caesium oleate stock solution may be injected and the resulting solution rapidly cooled to form perovskite CsPbBr nanoparticles. Purification may be performed using centrifugation.

The application relates to a large-size rare earth doped phenethylamine lead bromide perovskite monocrystal preparation method and perovskite monocrystal, and solves the technical problems that the preparation of the existing large-size rare earth doped two-dimensional perovskite monocrystal needs higher nucleation supersaturation, the preparation period is long, and part of the rare earth bromide is extremely easy to absorb moisture, thereby reducing the crystal quality. The large-size rare earth doped phenethylamine lead bromide perovskite monocrystal preparation method and perovskite monocrystal comprise the following steps: 1) weighing; phenethylamine hydrobromide, lead bromide and rare earth metal bromide are weighed and placed in a glass bottle; 2) obtaining a precursor solution; 3) obtaining a millimeter-level size crystal; 4) screening a seed crystal; and 5) seed crystal growth. In step 4), the open container B is placed at a preset temperature until the seed crystal continues to grow into a rare earth doped phenethylamine lead bromide perovskite monocrystal with a predetermined size, and the size can reach a centimeter level, which has an important supporting role in promoting the performance research of the rare earth doped two-dimensional perovskite monocrystal.

The invention discloses a preparation method of a gamma detector array based on a single crystal material, and relates to the technical field of gamma detection. The invention provides a preparation method of a perovskite single crystal material. The preparation method comprises the following steps: mixing methyl ammonium bromide powder and lead bromide powder, and dissolving in an N, N-dimethylformamide solvent to obtain an MAPbBr3 precursor solution; the preparation method comprises the following steps: dissolving formamidine chloride in an N, N-dimethylformamide solvent to obtain an FACl precursor solution; taking the FACl precursor solution, adding the MAPbBr3 precursor solution, mixing and clarifying to obtain an MAPbBr3-FACl solution; and filtering the MAPbBr3-FACl solution solvent, volatilizing and baking to obtain the perovskite single crystal material. The invention further provides a gamma ray detector array based on the perovskite single crystal material and a preparation method of the gamma ray detector array. The gamma ray detector array comprises the perovskite single crystal material, a low-power function metal layer and a high-power function metal layer, wherein the low-power function metal layer and the high-power function metal layer are deposited on the two faces of the perovskite single crystal material respectively.

The invention particularly relates to a neodymium-doped butylamine lead bromide single crystal with differentially adjustable luminescence decay time under gamma / alpha ray excitation, and solves the technical problem that the existing two-dimensional perovskite performance regulation and control method is difficult to realize differentially regulate and control the response of different radiation rays. The neodymium-doped butylamine lead bromide single crystal with differentially adjustable luminescence decay time under gamma / alpha ray excitation is prepared by the following method: 1) weighing; the preparation method comprises the following steps: weighing butylamine hydrobromide, lead bromide and neodymium bromide, and putting into a glass bottle; the concentration ratio of butylamine hydrobromide to lead bromide to neodymium bromide is 2: 1: (0.2-0.7); 2) obtaining a precursor solution; 3) obtaining a crystal; the precursor solution is filtered and then put into a glass beaker to be crystallized, the neodymium-doped butylamine lead bromide single crystal is obtained, and the decay time of response of the two-dimensional perovskite to gamma / alpha rays can be adjusted differentially.

The application discloses alkali metal doped perovskite single crystal material and a preparation method and application thereof. A high-concentration alkali metal halide is introduced into a perovskite aqueous phase precursor, and an alkali metal doped perovskite single crystal is precipitated through a cooling method. The traditional cesium lead bromide perovskite light emitting wavelength band is near 520 nm, and wide spectrum emission cannot be realized. The scheme can prepare a centimeter level perovskite CsPb2Br5 single crystal with wide spectrum emission. Test results show that the alkali metal doped perovskite CsPb2Br5 single crystal fluorescence spectrum covers a visible light and near infrared light wavelength band (500-1000 nm).

The invention relates to a preparation method of Na+ / Cu2+ ions co-doped cesium lead bromide perovskite quantum dots, products and applications thereof, which belongs to the technical field of modification research of perovskite quantum dots. The invention discloses a preparation method of Na+ / Cu2+ ions co-doped cesium lead bromide (CsPbBr3) perovskite quantum dots, which adopts lead bromide (PbBr2), oleic acid (OA), oleylamine (OAm), sodium ion precursors and copper ion precursors for the reaction preparation in octadecene (ODE), in which copper ions (Cu2+) and sodium ions (Na+) substitute A and B crystal sites in cesium lead bromide (CsPbBr3) perovskite fluorescent quantum dots respectively. The quantum dots have been effectively improved in photoluminescence quantum yield, thermal stability, etc., and can be used as an active layer to fabricate light emitting diodes which achieve the tuning of emission color from green to blue.

The invention relates to the technical field of nano material preparation, and discloses formamidine acetate doped CsPbBr3 perovskite nanocrystals and a water phase preparation method thereof.The method comprises the steps that firstly, lead bromide, cesium bromide, formamidine acetate and dimethylacetamide are mixed, and a uniformly-doped precursor solution containing formamidine acetate is prepared under the ultrasonic concussion condition; sequentially adding oleylamine and 5-bromovaleric acid into the precursor solution according to a specific sequence, and carrying out ultrasonic-assisted in-situ surface ligand modification; and finally, rapidly injecting the precursor solution into deionized water, inducing crystallization by using the polarity difference of the solvent, centrifuging to remove the precipitate, and taking the supernatant to obtain the target product. According to the preparation method disclosed by the invention, the structural stability of the CsPbBr3 nanocrystal is remarkably improved through doping of formamidine acetate (FA) to a lattice A site and synergistic coordination of acetate. The obtained nanocrystal has a cubic crystal phase structure and can be stably dispersed in a water phase system, and the technical problem that a traditional perovskite material is easy to decompose when meeting water is solved.

The invention discloses a blue light CsPbBr3 superlattice and a preparation method and application thereof, and belongs to the technical field of perovskite material preparation. The preparation method comprises the following steps: in a ketone solvent, reacting 4-hydroxytetraphenylethylene, 1, 3-dibromopropane and potassium carbonate to obtain (2-(4-(3-bromopropoxy) phenyl) ethylene-1, 1, 2-triyl) tribenzene; in an alcohol solvent, reacting the product with trimethylamine to obtain N, N-dimethyl-N-(3-(4-(1, 2, 2-triphenyl vinyl) phenoxy) propyl) methyl ammonium; dissolving the ligand in a halogenated hydrocarbon organic solution to obtain a ligand solution; and sequentially adding the ligand solution and the cesium oleate solution into the lead bromide solution, and carrying out ion exchange reaction at normal temperature to obtain the blue-light CsPbBr3 superlattice. The tetraphenyl ethylene quaternary ammonium salt molecules are introduced, so that the stability and highly ordered self-assembly of the nanosheet are improved.

The invention discloses a preparation method of a CsPbBr3 single crystal, and belongs to the technical field of novel nano materials. According to the technical scheme, the preparation method comprises the following steps: firstly, dissolving cesium bromide and lead bromide in a DMSO solvent, adding 4-bromobutyric acid, and cooling and stirring to obtain a mixed solution I; sufficiently mixing absolute methanol, cyclohexanol and DMF (Dimethyl Formamide) to obtain a mixed solution II; fully mixing the mixed solution I and the mixed solution II to obtain a precursor solution; and placing a seed crystal in the precursor solution, then putting the precursor solution and the container into preheated silicone oil, and preparing the CsPbBr3 single crystal by adopting a temperature inversion crystallization method. According to the method, methanol and 4-bromobutyric acid are introduced into a precursor solution, the solubility of the precursor solution can be reduced by introducing methanol, the slope of a solubility curve of CsPbBr3 at 85-90 DEG C is reduced, the growth speed of CsPbBr3 is reduced, the crystal quality is improved, the solubility curve of CsPbBr3 is monotonically reduced by introducing 4-bromobutyric acid, and the crystal quality is improved. The CsPbBr3 can be separated out at the temperature of about 60 DEG C, so that the growth temperature is reduced. The high-quality CsPbBr3 single crystal is obtained through the growth of the process disclosed by the invention.

This invention provides a co-encapsulation method for highly stable perovskite quantum dots, comprising the following preparation steps: S1, mixing and grinding a low-crystallinity all-silica zeolite carrier, cesium bromide, and lead bromide to obtain a precursor mixture; S2, heating the precursor mixture to allow the cesium, lead, and halogen components to enter the pores of the low-crystallinity all-silica zeolite carrier, and crystallizing under the confinement of the pores to form CsPbBr3 perovskite quantum dots; S3, contacting the product obtained in step S2 with an aqueous potassium chloride solution and performing hydrothermal treatment to obtain zeolite-encapsulated CsPbBr3 perovskite quantum dots containing lead hydroxide chloride. This invention can reduce the adverse effects of chlorine sources on direct halogen exchange in the perovskite quantum dot bulk lattice and promote the participation of chlorine sources in the formation of a stable protective structure at the carrier interface, thereby improving the stability of perovskite quantum dots.

The invention relates to a miRNA fluorescent nanoprobe based on hydrophilic inorganic cesium-lead-bromine perovskite as well as a preparation method and sensing application of the miRNA fluorescent nanoprobe, and belongs to the technical field of biosensing. The preparation method comprises the following steps: firstly, respectively dispersing two hydrophilic inorganic cesium-lead-bromine perovskite nano-materials in a solution, respectively modifying ssDNA to the surfaces of the two hydrophilic inorganic cesium-lead-bromine perovskite nano-materials through amidation reaction, and finally, reacting with MnO2 nanosheets, so as to construct Cs4PbBr6 / CsPbBr3-Mn NCs-ssDNA / MnO2 and Cs4PbBr6 / CsPbBr3-Mn NCs-ssDNA / MnO2 fluorescent nano-probes, i.e., Cs4PbBr6 / CsPbBr3-Mn NCs-ssDNA / MnO2 fluorescent nano-probes. The method is applied to quantitative detection of two miRNAs in the field of biosensing. Compared with other detection methods, the synthesis method of the inorganic cesium-lead-bromine perovskite nanoparticles used in the method is simple and rapid, complex surface group modification is not needed, and simultaneous detection of the two miRNAs can be achieved. In addition, the method is successfully applied to analysis and detection of miRNA-21 and miRNA-10b in a serum sample and a tumor cell lysis solution.