Quantum dot and preparation method thereof

A technology for quantum dots and dispersions, applied in the field of quantum dots and their preparation, can solve the problems of high toxicity, maintain between 20-50%, low photoluminescence, etc., and achieve environmental friendliness, high monodispersity, high The effect of luminous properties

Active Publication Date: 2018-11-13
SUZHOU XINGSHUO NANOTECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, the current Cd-based quantum dots have caused major environmental problems: (1) Cadmium is an experimental teratogenic and mutagenic substance, and most cadmium compounds are classified as highly toxic substances, so that Cd-based quantum dots have potentially highly toxic
(2) The experimental operation process of preparing quantum dots with cadmium-containing precursors is highly demanding, requiring professionals to carefully and carefully design experiments to ensure safety, and the cost of disposing of cadmium-containing wastes is high, which makes the cost issue a constraint on the size of quantum dots. One of the most important factors for mass production and widespread use
The ZnSe nanocrystals synthesized in earlier studies showed low photoluminescence and poor size distribution, and gas precursors and highly toxic and air-sensitive precursors, such as diethylzinc, trioctyl, etc., were used in the reaction. Phosphine, tetrabutylphosphine, tetrabutylphosphine oxide, the average quantum efficiency can only be maintained between 20-50%
Recently, in the report on phosphorus-free ZnSe quantum dots, although the quantum efficiency of ZnSe quantum dots can reach 40%, the quantum efficiency of its core ZnSe quantum dots is not stable.

Method used

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preparation example Construction

[0049] The quantum dots obtained by the above new preparation method have the following characteristics:

[0050] (1) All precursors used in the present invention are air stable.

[0051] That is to say, do not use the following precursors of ZnSe or ZnS quantum dots reported in the present invention in the new synthesis method: a, high heat precursors, such as diethylzinc, trioctylphosphine, tributylphosphine And other reagents sensitive to air or moisture; b, trioctylphosphine oxide; c, environmental reaction reagents such as hydrogen sulfide;

[0052] (2) Use weak binding ligands, such as aliphatic amines, to increase the activity of zinc precursors during the synthesis process;

[0053] (3) The particle diameter of the prepared quantum dot product is in the scope of 2.5-9nm;

[0054] (4) The quantum dot product is excited by ultraviolet light or ultraviolet light source, and has ultraviolet photoluminescence in the range of 370-450nm. By adjusting the particle size of qu...

Embodiment 1

[0068] Preparation of ZnSe quantum dots with high monodispersity and high fluorescence:

[0069] Into a 250mL three-necked flask, add 300mg of zinc stearate, 20mL of octadecene and 0.2mL of triheptylamine, vacuumize the flask at room temperature for 30min, then heat the flask to 90°C while maintaining the vacuum for 15min, pass into argon. The flask was heated to 290°C under an argon atmosphere. Add 0.1 mL of 2 mol / L selenium dispersion solution under the protection of argon into the flask with a 1 mL syringe. Keep the flask at 290°C, cool to 260°C after 3min, and keep the temperature for 90min. At different time points, a small portion of the reaction solution was extracted for optical absorption spectrum and fluorescence spectrum test, so as to monitor the reaction process. When the quantum dots grew to the desired size, the flask was naturally cooled to room temperature. To the resulting slurry of quantum dot products was added 300 mL of methanol to induce quantum dot p...

Embodiment 2

[0072] Preparation of ZnSe quantum dot cores with high monodispersity:

[0073] Into a 100mL three-necked flask, add 300mg of zinc stearate, 6mL of octadecene and 0.2mL of triheptylamine, vacuumize the flask at room temperature for 30min, then heat the flask to 110°C while maintaining the vacuum for 15min, pass into argon. Under an argon atmosphere, the flask was heated to 290° C., and 0.2 mL of a 2 mol / L octadecene-selenium dispersion was added under the protection of argon. After 10 minutes, the flask was heated to 300°C and kept for 20 minutes. Next, raise the temperature to 310°C, keep it warm for 5 minutes, then lower the temperature to 300°C, keep it warm for 11 minutes, continue to cool down to 290°C, and keep it warm for 5 minutes. Heating was stopped, and the flask was naturally cooled to room temperature. At this time, the fluorescence emission peak is at 412nm, the half-peak width is 20.4nm, and the quantum yield is 14%.

[0074] The dispersion of core ZnSe quan...

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Abstract

The invention discloses a quantum dot and a preparation method thereof. Compared with the prior art, the quantum dot has the advantages that the synthesized precursor and steps are environment-friendly, any heavy metal element is not contained in the product, and the photoluminescence spectrum is particular and excellent; specifically, the range of fluorescence transmission peak is 370 to 450nm, the semi-height width of the fluorescence transmission peak is 10.8 to 20nm, and the efficiency of fluorescence quantum is 47 to 88%; the size of the prepared nanometer crystal is 1.5 to 9mm, and the deviation is smaller than 10%; the quantum dot specifically comprises ZnSe (zinc selenide), ZnSe / ZnS (zinc sulfide) and ZnSe / ZnSeS / ZnS.

Description

[0001] Cross References to Related Applications [0002] This application claims the priority of the Chinese patent application "201710450162.9" entitled "A heavy metal-free high-brightness blue-violet light-emitting quantum dot and its preparation method" filed on June 15, 2017, the entire content of which is incorporated by reference into this article. technical field [0003] The invention belongs to the technical field of nanometer materials, and in particular relates to a quantum dot and a preparation method thereof. Background technique [0004] Quantum dots have higher performance, lifetime and energy efficiency than other fluorescent materials, and have great application value in the fields of display technology, biological imaging, solar cells and image sensors. Specifically, CdSe, CdS, and CdTe quantum dots with a diameter of 2-10 nm have unique optical properties, including: (1) High brightness: a single quantum dot can emit as much light as a single organic dye ...

Claims

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Application Information

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IPC IPC(8): C09K11/02C09K11/88B82Y40/00
CPCB82Y40/00C09K11/02C09K11/88C09K11/883
Inventor 王允军
Owner SUZHOU XINGSHUO NANOTECH CO LTD
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