Carbon dots, preparation method therefor, carbon-dot composite material, preparation method therefor and luminescent LED (Light Emitting Diode)

Abstract

The invention provides a preparation method for carbon dots. The preparation method comprises the steps: mixing citric acid and urea in a solvent, and then, carrying out heating, so as to obtain a reaction solution; and carrying out centrifugal separation on the reaction solution, so as to obtain precipitates, i.e., the carbon dots, wherein the solvent is one or a mixture of two of water, glycerine and dimethylformamide. According to method, visible-light-all-waveband-luminescent carbon dots are prepared through adopting different solvents, and thus, the carbon-dot composite material provided by the invention can emit light in all wave band of visible light, particularly, white-light carbon-dot composite materials of different color coordinates and color temperatures can be obtained by adopting the carbon dots of different colors. Furthermore, the carbon-dot composite material provided by the invention employs silicon dioxide as a dispersion matrix, so that gathered induced fluorescence quenching can be inhibited, and the composite material has relatively high quantum efficiency. The invention further provides the preparation method for the carbon dots, the carbon-dot composite material, a preparation method therefor and a luminescent LED (Light Emitting Diode).

Description

technical field [0001] The invention relates to the technical field of nanomaterials, in particular to a carbon nano-dot and a preparation method thereof, a carbon nano-dot composite material and a preparation method thereof, and a light-emitting LED. Background technique [0002] Carbon nanodots (Carbon dots, CDots) are a new type of luminescent carbon nanomaterials, which have small particle size, high fluorescence stability, no light flicker, wide and continuous excitation spectrum, tunable emission wavelength, and biocompatibility. It is considered as a potential substitute for organic dyes and semiconductor quantum dots due to its good properties and low toxicity. However, carbon nanodots will undergo serious fluorescence quenching due to aggregation in the solid state, which severely limits the application of carbon nanodots in LED display and lighting. [0003] In order to solve the problem of fluorescence quenching of carbon nanodots, carbon nanodots are generally d...

AI Technical Summary

Problems solved by technology

However, carbon nanodots will undergo severe fluorescence quenching due to aggregation in the solid state, which severely limits the application of carbon nanodots in LED display and lighting.

[0003] In order to solve the problem of fluorescence quenching of carbon nanodots, carbon nanodots are generally dispersed in polymer matrices to prepare composite materials. Common polymer matrices such as siloxane, methyl methacrylate and starch fibers, etc., but using The quantum efficiency of carbon nanodot composites obtained by these dispersed matrices is low, and the efficiency of carbon nanodot composites needs to be further improved

Moreover, at present, the solid-state luminescence of most carbon nanodot composites is located in short-wavelength bands such as blue-green regions, and less in long-waveband regions such as red-orange, and white light composite materials based entirely on carbon nanodots have not yet been reported.

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