A kind of carbon nitride quantum dot and its preparation method and application

A technology of carbon nitride and quantum dots, which is applied in the direction of chemical instruments and methods, applications, household appliances, etc., can solve the problems that limit the wide application of fluorescent inks, the information cannot be read directly, and the adverse effects of the environment, so as to achieve stable luminescence, The effect of uniform shape and simple preparation method

Active Publication Date: 2020-09-04
ZHENGZHOU UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Its preparation method includes nitric acid reflux, hydrothermal and ultrasonic treatment, which takes a long time and will have adverse effects on the environment
In addition, the fluorescence emitted by the prepared carbon nitride quantum dots is in the invisible region, and the information written by the quantum dots cannot be read directly, and the fluorescent signal must be converted into readable information by a specific instrument
These will limit the wide application of the fluorescent ink

Method used

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  • A kind of carbon nitride quantum dot and its preparation method and application
  • A kind of carbon nitride quantum dot and its preparation method and application
  • A kind of carbon nitride quantum dot and its preparation method and application

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preparation example Construction

[0030] The preparation method of the above-mentioned carbon nitride quantum dots comprises the following steps:

[0031] (1) Mix nitrogen and carbon-containing precursors with two kinds of chloride salts in a mortar, grind them evenly and transfer them into a crucible;

[0032] (2) Put the crucible containing the mixture in the muffle furnace, cover the crucible lid, and calcinate to obtain a light yellow frit;

[0033] (3) Wash the obtained frit with hydrochloric acid for 3 to 5 times to remove salt ions, disperse the obtained precipitate in water to form a suspension, and then centrifuge, the obtained supernatant is the carbon nitride quantum dot solution, freeze-dried carbon nitride quantum dots.

[0034] In the preparation method of the invention, nitrogen and carbon-containing substances are used as precursors, molten salts are used as solvents and catalysts, and carbon nitride quantum dots are obtained through one-step reaction. The preparation method of the invention ...

Embodiment 1

[0053] Preparation of carbon nitride quantum dots:

[0054] Take 8.0g of melamine and add it to the mixed salt of 11.2g of sodium chloride (5g) and potassium chloride (6.2g), thoroughly grind it evenly, transfer it into a crucible with a cover, put the crucible in a muffle furnace, 700°C Calcined for 5h, a light yellow frit was obtained.

[0055] Wash the frit 3 times with hydrochloric acid to remove salt ions, disperse the obtained precipitate in water to obtain a suspension, centrifuge at 6000rpm for 10min, and obtain a supernatant solution that is the carbon nitride quantum dot solution, and freeze-dry to obtain a white solid powder.

[0056] After XRD identification, the product is carbon nitride quantum dots, see figure 1 . figure 2 is the transmission electron microscope picture of the obtained product, it can be seen that the carbon nitride quantum dots have a uniform appearance and an average diameter of about 3.5 nm. The carbon nitride quantum dot aqueous solution...

Embodiment 2

[0058] Preparation of carbon nitride quantum dots:

[0059] Take 16.0g of urea and add it to the mixed salt of 11.2g of sodium chloride (6.7g) and lithium chloride (4.5g), fully grind it evenly, and transfer it into a crucible with a cover. The crucible was placed in a muffle furnace and calcined at 600°C for 2h to obtain a light yellow frit.

[0060] Wash the frit 5 times with hydrochloric acid to remove salt ions, disperse the obtained precipitate in water to obtain a suspension, centrifuge at 10000rpm for 10min, and the supernatant is the carbon nitride quantum dot solution.

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Abstract

The invention provides a method of producing a carbon nitride quantum dot and belongs to the field of nano-material science. The preparation method includes a step of performing a one-step reaction with substances containing nitrogen and carbon as precursors and fused salt as a solvent and a catalyst. The preparation method has simple operations, is green, environment-friendly and low-cost and allows large-scale production. The carbon nitride quantum dot has uniform appearance and controllable size, can be dispersed in water to form a colorless transparent solution; under excitation of ultraviolet light (wavelengths being 254 and 365 nm), the water solution emits blue fluorescence stably. In addition, by adding special substance, the fluorescence of the quantum dot can be quenched or restored. Based on the properties, the carbon nitride quantum dot, when being applied as ink for writing information, multi-encryption to the information is achieved and security of the information is guaranteed, thus achieving effective anti-faking.

Description

technical field [0001] The invention relates to a carbon nitride quantum dot and its preparation method and application, belonging to the field of nanometer material science. Background technique [0002] Currently, anti-counterfeiting of important documents, currencies and brands remains a challenge. Using the fluorescence of writing materials to encrypt information multiple times can effectively prevent information from being forged or copied. Many fluorescent materials, such as semiconductor quantum dots, lanthanum-doped nanomaterials, and metal-organic frameworks, have been used as fluorescent inks to prevent counterfeiting. Recently, carbon nitride quantum dots are expected to be used as fluorescent ink materials due to their stable fluorescence emission and non-toxicity. [0003] Chinese patent document CN 104861784 B discloses a carbon nitride quantum dot fluorescent ink and a preparation method thereof. The preparation method includes three treatment processes of ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K11/65C09D11/50B82Y20/00B82Y40/00
CPCB82Y20/00B82Y40/00C09D11/50C09K11/65
Inventor 李中军王雅苹王建设张俊雅
Owner ZHENGZHOU UNIV
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