A kind of hypergravity preparation method of lead sulfide quantum dots

Abstract

The invention discloses a supergravity preparation method of lead sulfide quantum dots, comprising the following steps: S1. dissolving lead salt in a mixed solution of water, ethanol and low-polarity organic solvent, adding a ligand, and stirring to form a microparticle Emulsion A; Dissolve sodium sulfide in water to form solution B; S2. Add microemulsion A to the hypergravity reactor, then add solution B to the hypergravity reactor, take out the reaction product solution C after the reaction, and place solution C in In an ice-water bath; S3. solution C is left to stand for a period of time, and obvious stratification occurs, and the solution containing lead sulfide quantum dots in the upper layer is separated, washed with water and ethanol respectively, and the purified lead sulfide quantum dots are dispersed in the lower electrode In a neutral solvent, lead sulfide quantum dots with good dispersibility were obtained. In the invention, the sodium sulfide aqueous solution with low toxicity is used as the sulfur source, and the supergravity technology is used together to prepare the lead sulfide quantum dots with uniform appearance and narrow particle size distribution, and the size is 3-7 nm.

Description

technical field [0001] The invention relates to the technical field of semiconductor nanomaterials, in particular to a method for preparing lead sulfide quantum dots under high gravity. Background technique [0002] Quantum dots, or semiconductor nanocrystals, are semiconductor nanoparticles in which excitons are restricted in three spatial dimensions, composed of II-VI, IV-VI or III-V elements, usually in the size of 1- Between 10nm. Quantum dots have broad application prospects in biomarkers, disease monitoring, displays, and solar cells, and have become research hotspots in physics, chemistry, materials science, and biomedicine. In recent years, IV-VI quantum dots have attracted more and more researchers' interest because of their large Bohr excitonic radius and unique multiple excitonic effect. [0003] As an important compound in IV-VI semiconductors, lead sulfide quantum dots have a large Bohr exciton radius (18nm) and a narrow energy band gap (0.41eV), which can be ...

AI Technical Summary

Problems solved by technology

The former is an organic sulfur source (TMS) 2 S, TAA, etc. prepare nanocrystals in organic solvents with strong coordination capabilities (TOP, OA, etc.). Instable, easy to deactivate, cost is also relatively expensive, not suitable for large-scale production; the latter is usually synthesized in aqueous solution or microemulsion, the sulfur source used is generally an aqueous solution of sodium sulfide, although the product size distribution is wide, The dispersion is not as good as the former product, and the fluorescence quantum yield is relatively low, but the operation is simple, the reaction conditions are mild, and the cost is low, which is suitable for large-scale production

[0004] Chinese patent CN106433634A discloses a method for preparing monodisperse lead sulfide quantum dots. The prepared lead sulfide quantum dots have the characteristics of high crystallinity, uniform size, mixed passivation of oleic acid and halogen, high-efficiency luminescence and high stability. The selected sulfur source is thioacetamide, which still has certain toxicity

[0005] Chinese patent CN108557874A discloses a method for preparing lead sulfide quantum dots by cation exchange. The invention uses cheap sulfur powder as the sulfur source, and adopts hot injection method to prepare cadmium sulfide quantum dots, and then undergoes cation exchange to obtain different absorption wavelengths. Lead sulfide quantum dots, but its preparation process is complicated, and the reaction temperature is high, and the energy consumption is high, which is not conducive to industrial production

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