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Preparation and applications of graphene quantum dots with white fluorescence emission properties

A graphene quantum dot and fluorescent emission technology, applied in the field of quantum dots, can solve the problems of difficult antibacterial materials, low brightness and efficiency of white light devices, and low reactive oxygen species production.

Active Publication Date: 2015-05-27
NANJING UNIV OF POSTS & TELECOMM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

These traditional synthetic methods mainly have the following problems: (1) the yield is relatively low, generally less than 10%, (2) the size uniformity of the prepared product is poor, (3) the purification is difficult
[0003] At the same time, when graphene quantum dots prepared by existing methods are used as light-emitting materials, the brightness and efficiency of white light devices are relatively low, and it is difficult to use them in lighting; when used as antibacterial materials, active oxygen The yield is low, it is difficult to use as an antibacterial material

Method used

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  • Preparation and applications of graphene quantum dots with white fluorescence emission properties
  • Preparation and applications of graphene quantum dots with white fluorescence emission properties
  • Preparation and applications of graphene quantum dots with white fluorescence emission properties

Examples

Experimental program
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Embodiment 1

[0034] A preparation method of graphene quantum dots with white fluorescent emission properties, comprising the steps of:

[0035] a. Put the nano-graphite powder with a particle size of 40~500nm into the mixed acid of sulfuric acid and nitric acid with a volume ratio of 3:1. After ultrasonic treatment for 2 hours, heat it to 80°C for 5 hours under the irradiation of microwave;

[0036] b, first filter the reaction product in step a with a 220nm microporous membrane, collect the filtrate and neutralize it to neutrality, then use a dialysis bag with a molecular weight cut-off of 1000 for dialysis several times, collect the liquid in the bag, and obtain graphene quantum dots; Its TEM photos and UV fluorescence spectra are as follows figure 1 and figure 2 As shown, the graphene quantum has good dispersion in water due to the many hydrophilic groups on the surface, and the size is about 1.8±0.3nm. The ultraviolet spectrum of graphene quantum dots has an absorption peak at 250nm...

Embodiment 2

[0040] A preparation method of graphene quantum dots with white fluorescent emission properties, comprising the steps of:

[0041] a. Put the nano-graphite powder with a particle size of 40~500nm into the mixed acid of sulfuric acid and nitric acid with a volume ratio of 3:1. After ultrasonic treatment for 2 hours, heat it to 120°C for 3 hours under the irradiation of microwave;

[0042]b, first filter the reaction product in step a with a 220nm microporous membrane, collect the filtrate and neutralize it to neutrality, and then dialyze it several times with a dialysis bag with a molecular weight cut-off of 3000, collect the liquid in the bag, and obtain graphene quantum dots;

[0043] c. After adjusting the pH value of the graphene quantum dots obtained in step b to 13, under the irradiation of microwaves, after heating to 200 ° C, react for at least 8 hours, and dialyze the reaction product with a dialysis bag with a molecular weight cut-off of 3000. The second time, the liq...

Embodiment 3

[0045] A preparation method of graphene quantum dots with white fluorescent emission properties, comprising the steps of:

[0046] a. Put the nano-graphite powder with a particle size of 40~500nm into the mixed acid of sulfuric acid and nitric acid with a volume ratio of 3:1. After ultrasonic treatment for 2 hours, heat it to 100°C for 4 hours under the irradiation of microwave;

[0047] b, first filter the reaction product in step a with a 220nm microporous membrane, collect the filtrate and neutralize it to neutrality, and then dialyze it several times with a dialysis bag with a molecular weight cut-off of 3000, collect the liquid in the bag, and obtain graphene quantum dots;

[0048] c. After adjusting the pH value of the graphene quantum dots obtained in step b to 13, under the irradiation of microwaves, after heating to 200 ° C, react for at least 8 hours, and dialyze the reaction product with a dialysis bag with a molecular weight cut-off of 3000. The second time, the li...

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Abstract

The invention discloses a preparation method and applications of graphene quantum dots with white fluorescence emission properties. The preparation method comprises the following steps: a, putting nano graphite powder into a mixed acid of sulphuric acid and nitric acid, and after the mixed acid is subjected to ultrasonic processing, under the irradiation of microwaves, heating for reacting; b, filtering a reaction product in the step a by using a microporous membrane firstly, collecting filtrate, neutralizing the filtrate until the filtrate is neutral, dialyzing the filtrate for several times by using a dialysis bag, and collecting liquid in the bag, so that a graphene quantum dot is obtained; c, after the pH value of the graphene quantum dots is adjusted to 13, under the irradiation of microwaves, heating for reacting, dialyzing the obtained reaction product for several times by using a dialysis bag, and collecting liquid in the bag, so that the graphene quantum dots with white fluorescence emission properties are obtained. The preparation and applications of the graphene quantum dots with white fluorescence emission properties disclosed by the invention have the main beneficial effects that synthesized graphene quantum dots are high in productivity, and have white light emission fluorescence properties.

Description

technical field [0001] The invention relates to a preparation method and application of graphene quantum dots with white fluorescent emission performance, belonging to the technical field of quantum dots. Background technique [0002] Graphene quantum dots refer to graphene nanomaterials with a size smaller than 10 nm. Due to its excellent and controllable optical properties and low biological toxicity, it has potential applications in biological probes, optoelectronic devices, etc. In order to further study the properties and application directions of graphene quantum dots, different synthesis methods have been proposed. Currently known traditional synthesis methods mainly include electrochemical method, chemical oxidation method, hydrothermal method, laser ablation method and so on. These traditional synthetic methods mainly have the following problems: (1) the yield is relatively low, generally less than 10%, (2) the size uniformity of the prepared product is poor, and (...

Claims

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Application Information

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IPC IPC(8): C09K11/65H01L33/50
CPCY02B20/00
Inventor 汪联辉罗志敏漆光骎杨栋梁翁丽星
Owner NANJING UNIV OF POSTS & TELECOMM