Preparation Of Luminescent Carbon Nano-materials And Its Application

In the field of fingerprint detection, powder light inspection method is widely used due to its simplicity of operation. It combines the advantages of powder inspection and light inspection, which can be simple, rapid and efficient to identify the details of the fingerprint characteristics. Rare earth luminescent material and semiconductor quantum dots are two most used fingerprint powders that have been reported. However, rare earth luminescent material and semiconductor quantum dots usually have a complex synthetic route, contain a large amount of heavy metal ions and has potential hazard for organisms.In the field of luminescent nano- materials and carbon nano- materials, because of their unique optical properties, good chemical stability, eas ily- modification, and the advantages of good biological compatibility, they have been one of the research hot spots, which can take the place of the traditional fluorescence fingerprint powder used in the detection of shallow fingerprints. As a new fluorescent nano- material to shine in solution and in solid state, g-C₃N₄ has been widely used in the field of fluorescent sensor. However, the g-C₃N₄ prepared by traditional method often shows weak fluorescence under solid state, which is not conducive to direct application. Carbon quantum dots as fluorescent carbon nano- material to the new members of the family is mainly used in the liquid phase. At present aggregation induced fluorescence quenching has not been effectively solved, which limits its application as light-emitting devices and fingerprint powder.This thesis respectively prepared g-C₃N₄ and carbon quantum dots which are luminescent in solid state, and explores their application in the field of shallow fingerprint detection. This expand the application of carbon quantum dots in liquid phase. Concrete research content is as follows:1.Using the melting salt as auxiliary, high temperature calcination method successfully got g-C₃N₄ nano-belt. By X-ray powder diffraction（XRD）, transmission electron microscope（TEM） tests to determine the product of the phase and morphology. Contrasting the results show that compared with the traditional method of block g-C₃N₄, nano-belt g-C₃N₄ has smaller size, higher fluorescence intensity, under the irradiation of ultraviolet lamp can emit visible blue light. Using solid powder brush technology to its successful application in brush different shallow fingerprints on the surface of the object and the fingerprints of different individuals.2.Using natural grains as raw materials, do not add any chemical reagent, a series of Carbon dots was prepared by hydrothermal method, which is luminescent both in solution and in solid states, we also explored the factors which affecting solid state luminescence. The size of Carbon dots depends on the precursor of grain, have similar chemical composition and similar optical properties, can effectively solve the fluorescence quenching of the Carbon dots, and preliminarily tried it’s application in the field of fingerprint detection.3.Investigated the luminescence properties of Carbon dots in solution, share the typical excitation depend emission. Carbon dots showed good resistance to the change of p H value of solution, ultraviolet light bleaching and the complex solution environment. Show strong selective to ferric iron ion, which can be used as a fluorescent probe to the detection of ferric iron ions in the solution. MTT colorimetric method were used to test the cytotoxicity of Carbon dots, results show that the Carbon dots has good biological compatibility, can be used for cell marking field.