Controlled Preparation Of Multicolor-Emissive Solid-State Carbon Dots And Their Applications In Light-Emitting Devices

Carbon Dots(CDs)is a novel nanomaterial with excellent photostability,low toxicity and simple preparation method,which can be widely used in lighting applications.Many optoelectronic devices usually need new solid-state fluorescent materials with multicolor and controllability as their light conversion layer.However,the presence of carbon dots in solid or aggregated state will result in fluorescence quenching,which limits the application of carbon dots in light-emitting devices.Therefore,the purpose of this study is to prepare polychromatic solid fluorescent carbon dots and apply them to light-emitting devices.In this paper,polychromatic solid fluorescent carbon dots were prepared by twostep hydrothermal synthesis and one-step microwave-assisted heating.The morphology and composition of the samples were characterized by TEM,XRD,XPS and Fourier transform infrared spectroscopy.The fluorescence properties and stability of the samples were evaluated by fluorescence spectrum,quantum yield,fluorescence lifetime,etc.The results are as follows:(1)Using the three different phenylenediamine isomer(o-phenylendiamine.oPD,m-phenylenediamine mPD and p-phenylenediamine pPD)and N,N-diethyl pphenylenediamine and the reaction temperature,the proportion of the first realized the carbon dots in aqueous solution of blue,green,yellow and red colors,using carbon dots achieved solid luminescent silica to package.It has excellent fluorescence properties and stability.XPS and infrared spectra prove that the red shift of its fluorescence emission peak is due to the increase of oxidation degree.(2)Using citric acid(CA),p-phenylenediamine(pPD)and 3-aminopropyl triethoxysilane(APTES)as raw materials,the blue,green,yellow and red solid luminescent carbon dots were prepared in one step only by changing the ratio of APTES/p PD.The prepared R-CDs,Y-CDs,G-CDs and B-CDs have excellent fluorescence properties and stability,and XPS proves that the increase of N element causes the red shift of the emission wavelength of CDs.(3)Using special chip excitation wavelength of 365 nm LED excitation multicolor fluorescent solid carbon,successfully created the multicolor LED device,inspire,red,green,and blue,solid state light emitting carbon dots,and by adjusting the color solid state light emitting carbon ratio,the quality of the produced color rendering index more than 80 standard of warm and white light leds.