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CN-122012091-A - Monodisperse lead sulfide quantum dot with adjustable size and wide range and preparation method thereof

CN122012091ACN 122012091 ACN122012091 ACN 122012091ACN-122012091-A

Abstract

The application relates to a monodisperse lead sulfide quantum dot with adjustable size and wide range and a preparation method thereof, belonging to the technical field of semiconductor quantum dots, wherein the preparation method comprises the steps of mixing a sulfur source, 1-octadecene and a ligand solvent to prepare a sulfur precursor solution; mixing oleic acid, lead oxide and 1-octadecene, heating and reacting under inert atmosphere to obtain lead oleate solution, injecting sulfur precursor solution into the lead oleate solution, heating and reacting to obtain lead sulfide quantum dot mixed solution, and purifying the lead sulfide quantum dot mixed solution to obtain the lead sulfide quantum dot. The lead sulfide quantum dot provided by the application has good crystallinity and monodispersity, the size distribution is 4-10nm, the controllable preparation of exciton peak positions (1400-2200 nm) of the lead sulfide quantum dot in a short-wave infrared range is realized, the particle size distribution is uniform, and the prepared lead sulfide quantum dot material can be applied to the fields of near-infrared (short-wave infrared) photoelectric detectors, solar cells and the like.

Inventors

  • LI HUIYU
  • Xie Qingjuan
  • FENG YONGJUN
  • WANG QILONG

Assignees

  • 北京化工大学

Dates

Publication Date
20260512
Application Date
20260130

Claims (10)

  1. 1. The monodisperse lead sulfide quantum dot is characterized in that the size of the lead sulfide quantum dot is 4-10nm, the size distribution deviation is less than or equal to 11.1%, and the first exciton absorption peak wavelength of the lead sulfide quantum dot is 1300-2220nm.
  2. 2. The monodisperse and wide-size-range-adjustable lead sulfide quantum dot according to claim 1, wherein the deviation of the size distribution of the lead sulfide quantum dot is less than or equal to 10%, and the first exciton absorption peak wavelength of the lead sulfide quantum dot is 1400-2200nm.
  3. 3. A method of preparing monodisperse and size-wide-area adjustable lead sulphide quantum dots according to any of claims 1 to 2, comprising the steps of: 1) Mixing a sulfur source, 1-octadecene and a ligand solvent to prepare a sulfur precursor solution; 2) Mixing oleic acid, lead oxide and 1-octadecene, and heating to react in an inert atmosphere to obtain a lead oleate solution; 3) Injecting the sulfur precursor solution prepared in the step 1) into the lead oleate solution prepared in the step 2), and heating for reaction to prepare a lead sulfide quantum dot mixed solution; 4) And 3) purifying the mixed solution prepared in the step 3) to obtain the lead sulfide quantum dot.
  4. 4. The method for preparing monodisperse and size-wide-range adjustable lead sulfide quantum dots according to claim 3, wherein in the step 1), the molar ratio of the sulfur source, 1-octadecene and ligand solvent is in the range of 1:5:10-1:10:5; The sulfur source is at least one of bis (trimethylsilyl) sulfide, thioacetamide and sulfur powder; the ligand solvent is any one of trioctyl phosphorus and oleylamine.
  5. 5. The method for preparing monodisperse and broad adjustable size lead sulfide quantum dots according to claim 4, wherein in step 1), the sulfur source is thioacetamide.
  6. 6. The method for preparing monodisperse and wide-size-range adjustable lead sulfide quantum dots according to claim 3, wherein in the step 2), the molar ratio of lead oxide, oleic acid and 1-octadecene is in the range of 1:16:36-1:4:48, and the temperature of the heating reaction is 140-160 ℃.
  7. 7. The method for preparing monodisperse and broad-range adjustable-size lead sulfide quantum dots according to claim 3, wherein in step 3), the molar ratio of lead to sulfur in the mixed solution is in the range of 1:4-4:1.
  8. 8. The method for preparing monodisperse and wide-size-range-adjustable lead sulfide quantum dots according to claim 3, wherein in the step 3), the heating reaction temperature is 130-170 ℃ and the reaction time is 2-6min.
  9. 9. The method for preparing monodisperse and wide-range adjustable size lead sulfide quantum dots according to claim 3, wherein in step 4), the purification treatment comprises mixing the mixed solution prepared in step 3) with an antisolvent, centrifuging, and collecting precipitate; the antisolvent is a mixed solution of isopropanol and acetone, and the volume ratio of the isopropanol to the acetone is 2:1.
  10. 10. The method for preparing monodisperse and size-wide-range tunable lead sulfide quantum dots according to claim 9, wherein in step 4), the purification treatment further comprises redissolving the obtained precipitate with a positive solvent; the positive solvent is n-hexane.

Description

Monodisperse lead sulfide quantum dot with adjustable size and wide range and preparation method thereof Technical Field The invention belongs to the technical field of semiconductor quantum dots, and particularly relates to a monodisperse lead sulfide quantum dot with adjustable size and wide range and a preparation method thereof. Technical Field Lead sulfide quantum dots (PbS CQDs) are used as typical IV-VI family narrow band gap semiconductor nano materials, and have remarkable quantum confinement effect, adjustable optical band gap (0.6-1.6 eV), larger exciton Bohr radius (about 18 nm) and excellent near infrared light absorption and emission characteristics, so that the lead sulfide quantum dots have wide application prospect in the front fields of solar cells, photodetectors, biological imaging, light-emitting diodes and the like. Therefore, the development of the PbS CQDs preparation technology with high quality, controllable size and single dispersion has important significance for promoting the performance improvement and industrial application of related photoelectric devices. Currently, various technological routes have been developed for the synthesis of PbS CQDs, mainly including solvothermal method, thermal injection method, atomic Layer Deposition (ALD), laser etching method, microwave assisted method, and the like. Although the atomic layer deposition method can realize the deposition accuracy of atomic level, the process parameters are complex, the quantum dots with different sizes need to correspond to different deposition conditions, the deposition rate is slow, the surface defects of the quantum dots are easy to increase, and the optical performance is attenuated, for example, literature "Ultra-wideband and flat-gain optical properties of the PbS quantum dots-doped silica fiber"（Opt. Express 27, 37900-37909 (2019)） reports that the preparation of a PbS film by adopting an ALD process has the quantum dot size regulation and control range limited to 3.65-4.45 nm, the absorption peak is positioned in the near infrared region, and the shortwave infrared band is difficult to cover. On the other hand, although the technology based on physical etching such as laser etching is suitable for a specific substrate, the problems of easy aggregation, poor monodispersity, wide size distribution and the like of quantum dots generally exist, and for example, as shown in literature "Preparation and characterization of PbS quantum dots by laser ablation technique in the presence of benzene"（J Mater Sci: Mater Electron 35, 30 (2024)）, the PbS CQDs obtained by the method have short absorption wavelength, insufficient size uniformity and strong dependence on the substrate. In contrast, the thermal injection method is more suitable for large-scale preparation of high-quality PbS CQDs because of the relatively simple process, lower cost and easy control of reaction conditions. The core of the method is that the precursor has activity, and the precursor with high activity can quickly release enough monomers in a reaction system, so that the concentration of the monomers can quickly reach a nucleation threshold value, thereby inducing uniform nucleation and laying a foundation for the controllable growth of subsequent quantum dots. In the synthesis of PbS CQDs by the thermal injection method, the chemical state of the lead precursor is relatively stable, so the selection of the sulfur source becomes a key factor in determining the rate of quantum dot synthesis, size distribution and monodispersity. In summary, the synthesis of PbS CQDs in the prior art still faces two significant challenges, namely (1) the lack of an ideal sulfur source with low cost, stable chemical properties and moderate activity to realize the controllability and uniformity of the quantum dot growth process, and (2) the difficulty in controllable preparation of PbS CQDs with large size is high, so that it is difficult to ensure good monodispersity and crystallization quality. Therefore, developing a preparation method based on a novel sulfur source, simple in process, capable of effectively regulating and controlling the size, and particularly capable of realizing synthesis of large-size monodisperse PbS CQDs becomes a technical problem to be solved in the field. Disclosure of Invention The invention aims to provide a monodisperse lead sulfide quantum dot with adjustable size and wide range and a preparation method thereof, and aims to realize controllable preparation of the lead sulfide quantum dot with high monodispersity and absorption wavelength covering short wave infrared band in a wide size range (4-10 nm) by selecting a proper sulfur source and accurately regulating and controlling reaction conditions. On one hand, the invention provides a monodisperse lead sulfide quantum dot with adjustable size and wide range, which adopts the following technical scheme: The lead sulfide quantum dot is monodisperse and has a size which is adjustab