Study On Preparation,Properties And Application Of Multicolor Carbon Dots

Carbon dots not only have excellent photoluminescence properties,but also have low toxicity,biocompatibility,high quantum yield,ultra-high specific surface area,chemical inertia,excellent electron transfer properties and so on.So far,CDs is widely regarded as a very promising nano material,which has great applications in different fields,including sensors,energy storage,drug delivery,biological imaging,catalysis and light emitting diodes(LEDs).However,the emission of carbon dots reported at present is mostly concentrated in the blue-green region,and there are few carbon dots emitting in the red and near-infrared regions.Therefore,it is very important to select appropriate precursors and adjust appropriate reaction conditions to prepare long wave emission carbon dots or a series of carbon dots.The specific work is as follows:(1)Using o-phenylenediamine as carbon source and under the action of nitric acid,a kind of CDs with near-infrared luminescence was synthesized by hydrothermal method,with the size of about 4.7 nm.The carbon dots are dispersed in organic solvents with different polarities,show different emission positions and emission colors,and can distinguish solvents with different polarities,that is,the so-called "solvation effect".In addition,this carbon dot can also detect trace water in ethanol.With the addition of water,the emission intensity at 605 nm gradually decreases,and the emission intensity at 360 nm remains unchanged.The detection range is 0-100%,LOD = 0.02%.In addition,we also prepared a series of carbon dots ? polymer films.The solvation effect in the solvent can be inherited into the solid state,which shows a broad application prospect in solid-state lighting(2)Using o-phenylenediamine and serine as carbon sources,five kinds of carbon dots were synthesized by hydrothermal method by simply adjusting the reaction temperature and acidity.Their emission positions changed from blue to red to form a panchromatic luminescence system.Through a series of transmission electron microscopy,Raman spectroscopy and solid UV characterization,it was found that the synthesized carbon dots accorded with the quantum size effect,that is,the emission position and size were linear,the emission position changes with the conjugate area.It is worth mentioning that CDs / PVA films were prepared based on the polychromatic luminescence characteristics of the system.The luminescence effect of carbon dots in solution can be well inherited into the solid matrix.At the same time,LEDs and WLED multi-color lighting devices based on CDs / PVA film are also fabricated.These applications confirm that polychromatic carbon dots have broad application prospects in solid-state lighting devices.