CN-122012097-A - Preparation method of CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot

CN122012097ACN 122012097 ACN122012097 ACN 122012097ACN-122012097-A

Abstract

The invention relates to a preparation method of a CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot, which comprises the steps of preparing an S-ODE precursor solution, an S-TOP precursor solution and a Se-TBP precursor solution, preparing a CdZnS core solution by using cadmium oxide, zinc acetate, oleic acid, 1-octadecene and an S-ODE precursor solution, preparing a CdZnS/ZnSe solution by using zinc acetate, oleic acid, 1-octadecene, a CdZnS core solution and a Se-TBP precursor solution, and preparing a CdZnS/ZnSe parabolic energy band structure quantum dot solution by using zinc acetate, oleic acid, 1-octadecene CdZnS/ZnSe solution and an S-TOP precursor solution. According to the preparation method of the three-shell collaborative design of the CdZnS core-ZnSe intermediate layer-ZnS shell, the high-efficiency and stable pure blue light emission is realized.

Inventors

WANG YUE
Hu Binjun
REN YINJUAN

Assignees

南京理工大学

Dates

Publication Date: 20260512
Application Date: 20260309

Claims (4)

1. A preparation method of CdZnS/ZnSe/ZnS parabolic energy band structure quantum dots is characterized by comprising the following steps: (1) S-ODE precursor solution, S-TOP precursor solution and Se-TBP precursor solution are prepared by dissolving S powder in 1-octadecene at an inert gas environment and a temperature of 150-180 ℃ to obtain S-ODE precursor solution with a concentration of 0.5mmol/mL, dissolving S powder in tri-n-octyl phosphine at an inert gas environment and a temperature of 130-150 ℃ to obtain S-TOP precursor solution with a concentration of 0.2mmol/mL, and dissolving Se powder in tributyl phosphate at an inert gas environment and a temperature of 130-150 ℃ to obtain Se-TBP precursor solution with a concentration of 0.2 mmol/mL; (2) Adding cadmium oxide, zinc acetate, oleic acid and 1-octadecene into a three-necked flask under the protection of argon, exhausting and dewatering for 30min at the temperature of 130 ℃, then raising the temperature to 300 ℃, injecting the S-ODE precursor solution prepared in the step (1) after stabilizing, reacting for 30min, cooling to room temperature to obtain a CdZnS nuclear crude product, purifying and dispersing the CdZnS nuclear crude product into the 1-octadecene to obtain the CdZnS nuclear solution, wherein the molar ratio of the cadmium oxide to the zinc acetate added into the three-necked flask is 1:5, the molar ratio of S in the S-ODE precursor solution to the total molar ratio of the cadmium oxide and the zinc acetate is 1:2, and the CdZnS nuclear crude product is dispersed in 0.4 mL of 1-octadecene after purifying; (3) Adding zinc acetate, oleic acid and 1-octadecene into another three-necked flask under the protection of argon, exhausting and dewatering for 30min at the temperature of 130 ℃, then raising the temperature to 280 ℃, injecting the CdZnS core solution prepared in the step (2) after stabilizing, then injecting the Se-TBP precursor solution prepared in the step (1) by using a peristaltic pump for multiple times, continuing to react for 30min after all injection, cooling to obtain a CdZnS/ZnSe core-shell intermediate crude product, purifying and dispersing in 1-octadecene to obtain a CdZnS/ZnSe solution, wherein each mmol of zinc acetate added into the other three-necked flask corresponds to 2.5mL of oleic acid, 10mL of 1-octadecene, 5mLCdZnS core solution and 5mL of Se-TBP precursor solution, and dispersing in 2 mL of 1-octadecene after purifying each 3mLCdZnS/ZnSe core-shell intermediate crude product; (4) Under the protection of argon, zinc acetate, oleic acid and 1-octadecene are added into a reaction bottle, the temperature is 130 ℃ and is exhausted and dehydrated for 30 minutes, then the temperature is raised to 280 ℃, the CdZnS/ZnSe solution prepared in the step (3) is injected after stabilization, then the S-TOP precursor solution prepared in the step (1) is injected by using a peristaltic pump, the reaction is carried out for 30 minutes and then the reaction is cooled to room temperature, and the obtained product is purified, so that the CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot solution taking normal hexane as a solvent is obtained, wherein each mmol of zinc acetate added into the reaction bottle corresponds to 2.5mL of oleic acid, 10mL of 1-octadecene, 5mL of CdZnS/ZnSe solution and 5mL of S-TOP precursor solution.
2. The preparation method of the CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot according to claim 1, which is characterized in that the purification step of the step (2) comprises the steps of adding n-hexane with the same volume as that of a CdZnS nuclear crude product and ethanol with the volume of 6 times that of the CdZnS nuclear crude product into the CdZnS nuclear crude product, uniformly mixing, centrifuging, discarding supernatant to obtain precipitate, dispersing the precipitate into n-hexane with the same volume as that of the CdZnS nuclear crude product, centrifuging, repeating for 2-3 times, discarding the precipitate to obtain supernatant, adding ethanol with the volume of 4 times that of the CdZnS nuclear crude product into the supernatant, centrifuging, discarding the supernatant to obtain precipitate, and thus completing the purification.
3. The preparation method of the CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot is characterized in that the purification step (3) comprises the steps of adding n-hexane and ethanol with the volume being the same as that of a CdZnS/ZnSe core-shell intermediate crude product into the CdZnS/ZnSe core-shell intermediate crude product, uniformly mixing, discarding supernatant fluid to obtain precipitate through centrifugal separation, dispersing the precipitate into n-hexane with the volume being the same as that of the CdZnS/ZnSe core-shell intermediate crude product, repeating the centrifugal separation for 2-3 times to discard the precipitate to obtain supernatant fluid, adding ethanol with the volume being 4 times that of the CdZnS/ZnSe core-shell intermediate crude product into the supernatant fluid, and continuing the centrifugal separation to discard the supernatant fluid to obtain precipitate, thereby completing the purification.
4. The preparation method of the CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot according to claim 1, which is characterized in that the purification step of the step (4) comprises the steps of adding n-hexane with the same volume and ethanol with the volume being 6 times that of the product, uniformly mixing, separating by centrifugation, discarding supernatant, dispersing precipitate in n-hexane with the same volume as the product, repeating the separation by centrifugation for 2-3 times, discarding the precipitate, and obtaining supernatant which is the CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot solution taking n-hexane as a solvent.

Description

Preparation method of CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot Technical Field The invention relates to the field of quantum dot synthesis technology and photoelectron material application, in particular to a preparation method of a CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot. Background The quantum dot as a semiconductor nanocrystal with unique size dependent optical characteristics has wide application prospect in the fields of display, illumination, photoelectric detection and the like. The blue light quantum dot is one of core materials for realizing full-color-gamut high-definition display, and the performance of the blue light quantum dot directly determines the color gamut width and color purity of the display device. Among many material systems, cdZnS-based quantum dots are considered as very potential candidate materials because they can achieve efficient emission in the blue band by precisely adjusting the components and have a narrower half-peak width. To improve the fluorescence quantum yield and stability of quantum dots, the main technical route is usually to use a core-shell structure, where a luminescent CdZnS core is most commonly coated with a wide-bandgap semiconductor material (such as ZnS). However, this structure still faces significant bottlenecks in the practical preparation of high performance blue quantum dots. Because of the large lattice mismatch between the CdZnS core and the ZnS shell, the direct epitaxial growth can cause high-density defects at the interface to become a non-radiative recombination center, which not only limits the further improvement of the fluorescence quantum yield, but also can cause spectrum broadening and red shift of emission wavelength, and pure and stable blue light is difficult to obtain. Meanwhile, the traditional single-layer shell structure is often insufficient in light, heat and environmental stability, and the shell layer is easy to degrade under severe conditions, so that the core material is exposed and fluorescence quenching is initiated. Although the introduction of a lattice interlayer (such as ZnSe) to form a graded shell is an effective idea for alleviating mismatch and improving stability, the existing preparation method still faces challenges in the aspect of precisely controllable growth of a multilayer structure. The complexity of the process makes the thickness of each shell layer, the interface components and the structure of the shell layer worse in controllability, and the reproducible and large-scale preparation with excellent stability is difficult to realize while ensuring high quantum yield. Therefore, developing a preparation method capable of accurately regulating and controlling a core-shell structure, high in process efficiency and good in repeatability to obtain the CdZnS-based blue light quantum dot with high fluorescence efficiency and excellent stability becomes a key for promoting commercial application of the CdZnS-based blue light quantum dot. Disclosure of Invention Aiming at the defects of weak exciton confinement, serious non-radiative recombination and poor stability of the existing blue light quantum dot, the invention provides a preparation method of a CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot, and high-efficiency and stable pure blue light emission is realized by a preparation method of three-shell collaborative design of a CdZnS core-ZnSe middle layer-ZnS shell. The preparation method of the CdZnS/ZnSe/ZnS parabolic energy band structure quantum dot comprises the following steps: (1) S-ODE precursor solution, S-TOP precursor solution and Se-TBP precursor solution are prepared by dissolving S powder in 1-octadecene at an inert gas environment and a temperature of 150-180 ℃ to obtain S-ODE precursor solution with a concentration of 0.5mmol/mL, dissolving S powder in tri-n-octyl phosphine at an inert gas environment and a temperature of 130-150 ℃ to obtain S-TOP precursor solution with a concentration of 0.2mmol/mL, and dissolving Se powder in tributyl phosphate at an inert gas environment and a temperature of 130-150 ℃ to obtain Se-TBP precursor solution with a concentration of 0.2 mmol/mL; (2) Adding cadmium oxide, zinc acetate, oleic acid and 1-octadecene into a three-necked flask under the protection of argon, exhausting and dewatering for 30min at the temperature of 130 ℃, then raising the temperature to 300 ℃, injecting the S-ODE precursor solution prepared in the step (1) after stabilizing, reacting for 30min, cooling to room temperature to obtain a CdZnS nuclear crude product, purifying and dispersing the CdZnS nuclear crude product into the 1-octadecene to obtain the CdZnS nuclear solution, wherein the molar ratio of the cadmium oxide to the zinc acetate added into the three-necked flask is 1:5, the molar ratio of S in the S-ODE precursor solution to the total molar ratio of the cadmium oxide and the zinc acetate is 1:2, and the CdZnS nuclear crude pro